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Remove vowels from a string
#include <stdio.h> void print_no_vowels(const char *s) { for (; *s != 0; s++) { switch (*s) { case 'A': case 'E': case 'I': case 'O': case 'U': case 'a': case 'e': case 'i': case 'o': case 'u': break; default: putchar(*s); break; } } } void test(const char *const s) { printf("Input  : %s\n", s); printf("Output : "); print_no_vowels(s); printf("\n"); } int main() { test("C Programming Language"); return 0; }
fn remove_vowels(str: String) -> String { let vowels = "aeiouAEIOU"; let mut devowelled_string = String::from(""); for i in str.chars() { if vowels.contains(i) { continue; } else { devowelled_string.push(i); } } return devowelled_string; } fn main() { let intro = String::from("Ferris, the crab, is the unofficial mascot of the Rust Programming Language"); println!("{}", intro); println!("{}", remove_vowels(intro)); }
Rename a file
#include <stdio.h> int main() { rename("input.txt", "output.txt"); rename("docs", "mydocs"); rename("/input.txt", "/output.txt"); rename("/docs", "/mydocs"); return 0; }
use std::fs; fn main() { let err = "File move error"; fs::rename("input.txt", "output.txt").ok().expect(err); fs::rename("docs", "mydocs").ok().expect(err); fs::rename("/input.txt", "/output.txt").ok().expect(err); fs::rename("/docs", "/mydocs").ok().expect(err); }
Repeat
#include <stdio.h> void repeat(void (*f)(void), unsigned int n) { while (n-->0) (*f)(); } void example() { printf("Example\n"); } int main(int argc, char *argv[]) { repeat(example, 4); return 0; }
fn repeat(f: impl FnMut(usize), n: usize) { (0..n).for_each(f); }
Repeat a string
#include <stdio.h> #include <stdlib.h> #include <string.h> char * string_repeat( int n, const char * s ) { size_t slen = strlen(s); char * dest = malloc(n*slen+1); int i; char * p; for ( i=0, p = dest; i < n; ++i, p += slen ) { memcpy(p, s, slen); } *p = '\0'; return dest; } int main() { char * result = string_repeat(5, "ha"); puts(result); free(result); return 0; }
std::iter::repeat("ha").take(5).collect::<String>();
Reverse a string
#include <stdio.h> #include <stdlib.h> #include <locale.h> #include <wchar.h> const char *sa = "abcdef"; const char *su = "as⃝df̅"; int is_comb(wchar_t c) { if (c >= 0x300 && c <= 0x36f) return 1; if (c >= 0x1dc0 && c <= 0x1dff) return 1; if (c >= 0x20d0 && c <= 0x20ff) return 1; if (c >= 0xfe20 && c <= 0xfe2f) return 1; return 0; } wchar_t* mb_to_wchar(const char *s) { wchar_t *u; size_t len = mbstowcs(0, s, 0) + 1; if (!len) return 0; u = malloc(sizeof(wchar_t) * len); mbstowcs(u, s, len); return u; } wchar_t* ws_reverse(const wchar_t* u) { size_t len, i, j; wchar_t *out; for (len = 0; u[len]; len++); out = malloc(sizeof(wchar_t) * (len + 1)); out[len] = 0; j = 0; while (len) { for (i = len - 1; i && is_comb(u[i]); i--); wcsncpy(out + j, u + i, len - i); j += len - i; len = i; } return out; } char *mb_reverse(const char *in) { size_t len; char *out; wchar_t *u = mb_to_wchar(in); wchar_t *r = ws_reverse(u); len = wcstombs(0, r, 0) + 1; out = malloc(len); wcstombs(out, r, len); free(u); free(r); return out; } int main(void) { setlocale(LC_CTYPE, ""); printf("%s => %s\n", sa, mb_reverse(sa)); printf("%s => %s\n", su, mb_reverse(su)); return 0; }
let mut buffer = b"abcdef".to_vec(); buffer.reverse(); assert_eq!(buffer, b"fedcba");
Reverse words in a string
#include <stdio.h> #include <ctype.h> void rev_print(char *s, int n) { for (; *s && isspace(*s); s++); if (*s) { char *e; for (e = s; *e && !isspace(*e); e++); rev_print(e, 0); printf("%.*s%s", (int)(e - s), s, " " + n); } if (n) putchar('\n'); } int main(void) { char *s[] = { "---------- Ice and Fire ------------", " ", "fire, in end will world the say Some", "ice. in say Some ", "desire of tasted I've what From ", "fire. favor who those with hold I ", " ", "... elided paragraph last ... ", " ", "Frost Robert -----------------------", 0 }; int i; for (i = 0; s[i]; i++) rev_print(s[i], 1); return 0; }
const TEXT: &'static str = "---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------"; fn main() { println!("{}", TEXT.lines() .map(|line| line.split_whitespace() .rev() .collect::<Vec<_>>() .join(" ")) .collect::<Vec<_>>() .join("\n")); }
Roman numerals_Decode
#include <stdio.h> int digits[26] = { 0, 0, 100, 500, 0, 0, 0, 0, 1, 1, 0, 50, 1000, 0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 10, 0, 0 }; #define VALUE(x) digits[(~0x20 & (x)) - 'A'] int decode(const char * roman) { const char *bigger; int current; int arabic = 0; while (*roman != '\0') { current = VALUE(*roman); bigger = roman; while (VALUE(*bigger) <= current && *++bigger != '\0'); if (*bigger == '\0') arabic += current; else { arabic += VALUE(*bigger); while (roman < bigger) arabic -= VALUE(* (roman++) ); } roman ++; } return arabic; } int main() { const char * romans[] = { "MCmxC", "MMVIII", "MDClXVI", "MCXLUJ" }; int i; for (i = 0; i < 4; i++) printf("%s\t%d\n", romans[i], decode(romans[i])); return 0; }
struct RomanNumeral { symbol: &'static str, value: u32 } const NUMERALS: [RomanNumeral; 13] = [ RomanNumeral {symbol: "M", value: 1000}, RomanNumeral {symbol: "CM", value: 900}, RomanNumeral {symbol: "D", value: 500}, RomanNumeral {symbol: "CD", value: 400}, RomanNumeral {symbol: "C", value: 100}, RomanNumeral {symbol: "XC", value: 90}, RomanNumeral {symbol: "L", value: 50}, RomanNumeral {symbol: "XL", value: 40}, RomanNumeral {symbol: "X", value: 10}, RomanNumeral {symbol: "IX", value: 9}, RomanNumeral {symbol: "V", value: 5}, RomanNumeral {symbol: "IV", value: 4}, RomanNumeral {symbol: "I", value: 1} ]; fn to_hindu(roman: &str) -> u32 { match NUMERALS.iter().find(|num| roman.starts_with(num.symbol)) { Some(num) => num.value + to_hindu(&roman[num.symbol.len()..]), None => 0, } } fn main() { let roms = ["MMXIV", "MCMXCIX", "XXV", "MDCLXVI", "MMMDCCCLXXXVIII"]; for &r in &roms { println!("{:2$} = {}", r, to_hindu(r), 15); } }
Roman numerals_Encode
#include <stdio.h> int main() { int arabic[] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1}; char roman[13][3] = {"M\0", "CM\0", "D\0", "CD\0", "C\0", "XC\0", "L\0", "XL\0", "X\0", "IX\0", "V\0", "IV\0", "I\0"}; int N; printf("Enter arabic number:\n"); scanf("%d", &N); printf("\nRoman number:\n"); for (int i = 0; i < 13; i++) { while (N >= arabic[i]) { printf("%s", roman[i]); N -= arabic[i]; } } return 0; }
struct RomanNumeral { symbol: &'static str, value: u32 } const NUMERALS: [RomanNumeral; 13] = [ RomanNumeral {symbol: "M", value: 1000}, RomanNumeral {symbol: "CM", value: 900}, RomanNumeral {symbol: "D", value: 500}, RomanNumeral {symbol: "CD", value: 400}, RomanNumeral {symbol: "C", value: 100}, RomanNumeral {symbol: "XC", value: 90}, RomanNumeral {symbol: "L", value: 50}, RomanNumeral {symbol: "XL", value: 40}, RomanNumeral {symbol: "X", value: 10}, RomanNumeral {symbol: "IX", value: 9}, RomanNumeral {symbol: "V", value: 5}, RomanNumeral {symbol: "IV", value: 4}, RomanNumeral {symbol: "I", value: 1} ]; fn to_roman(mut number: u32) -> String { let mut min_numeral = String::new(); for numeral in NUMERALS.iter() { while numeral.value <= number { min_numeral = min_numeral + numeral.symbol; number -= numeral.value; } } min_numeral } fn main() { let nums = [2014, 1999, 25, 1666, 3888]; for &n in nums.iter() { println!("{:2$} = {}", n, to_roman(n), 4); } }
Roots of a function
#include <math.h> #include <stdio.h> double f(double x) { return x*x*x-3.0*x*x +2.0*x; } double secant( double xA, double xB, double(*f)(double) ) { double e = 1.0e-12; double fA, fB; double d; int i; int limit = 50; fA=(*f)(xA); for (i=0; i<limit; i++) { fB=(*f)(xB); d = (xB - xA) / (fB - fA) * fB; if (fabs(d) < e) break; xA = xB; fA = fB; xB -= d; } if (i==limit) { printf("Function is not converging near (%7.4f,%7.4f).\n", xA,xB); return -99.0; } return xB; } int main(int argc, char *argv[]) { double step = 1.0e-2; double e = 1.0e-12; double x = -1.032; double xx, value; int s = (f(x)> 0.0); while (x < 3.0) { value = f(x); if (fabs(value) < e) { printf("Root found at x= %12.9f\n", x); s = (f(x+.0001)>0.0); } else if ((value > 0.0) != s) { xx = secant(x-step, x,&f); if (xx != -99.0) printf("Root found at x= %12.9f\n", xx); else printf("Root found near x= %7.4f\n", x); s = (f(x+.0001)>0.0); } x += step; } return 0; }
use roots::find_roots_cubic; fn main() { let roots = find_roots_cubic(1f32, -3f32, 2f32, 0f32); println!("Result : {:?}", roots); }
Roots of unity
#include <stdio.h> #include <math.h> int main() { double a, c, s, PI2 = atan2(1, 1) * 8; int n, i; for (n = 1; n < 10; n++) for (i = 0; i < n; i++) { c = s = 0; if (!i ) c = 1; else if(n == 4 * i) s = 1; else if(n == 2 * i) c = -1; else if(3 * n == 4 * i) s = -1; else a = i * PI2 / n, c = cos(a), s = sin(a); if (c) printf("%.2g", c); printf(s == 1 ? "i" : s == -1 ? "-i" : s ? "%+.2gi" : "", s); printf(i == n - 1 ?"\n":", "); } return 0; }
use num::Complex; fn main() { let n = 8; let z = Complex::from_polar(&1.0,&(1.0*std::f64::consts::PI/n as f64)); for k in 0..=n-1 { println!("e^{:2}πi/{} ≈ {:>14.3}",2*k,n,z.powf(2.0*k as f64)); } }
Rosetta Code_Count examples
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <curl/curl.h> #include "wren.h" struct MemoryStruct { char *memory; size_t size; }; static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) { size_t realsize = size * nmemb; struct MemoryStruct *mem = (struct MemoryStruct *)userp; char *ptr = realloc(mem->memory, mem->size + realsize + 1); if(!ptr) { printf("not enough memory (realloc returned NULL)\n"); return 0; } mem->memory = ptr; memcpy(&(mem->memory[mem->size]), contents, realsize); mem->size += realsize; mem->memory[mem->size] = 0; return realsize; } void C_bufferAllocate(WrenVM* vm) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenSetSlotNewForeign(vm, 0, 0, sizeof(struct MemoryStruct)); ms->memory = malloc(1); ms->size = 0; } void C_bufferFinalize(void* data) { struct MemoryStruct *ms = (struct MemoryStruct *)data; free(ms->memory); } void C_curlAllocate(WrenVM* vm) { CURL** pcurl = (CURL**)wrenSetSlotNewForeign(vm, 0, 0, sizeof(CURL*)); *pcurl = curl_easy_init(); } void C_value(WrenVM* vm) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenGetSlotForeign(vm, 0); wrenSetSlotString(vm, 0, ms->memory); } void C_easyPerform(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); curl_easy_perform(curl); } void C_easyCleanup(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); curl_easy_cleanup(curl); } void C_easySetOpt(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); CURLoption opt = (CURLoption)wrenGetSlotDouble(vm, 1); if (opt < 10000) { long lparam = (long)wrenGetSlotDouble(vm, 2); curl_easy_setopt(curl, opt, lparam); } else if (opt < 20000) { if (opt == CURLOPT_WRITEDATA) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenGetSlotForeign(vm, 2); curl_easy_setopt(curl, opt, (void *)ms); } else if (opt == CURLOPT_URL) { const char *url = wrenGetSlotString(vm, 2); curl_easy_setopt(curl, opt, url); } } else if (opt < 30000) { if (opt == CURLOPT_WRITEFUNCTION) { curl_easy_setopt(curl, opt, &WriteMemoryCallback); } } } WrenForeignClassMethods bindForeignClass(WrenVM* vm, const char* module, const char* className) { WrenForeignClassMethods methods; methods.allocate = NULL; methods.finalize = NULL; if (strcmp(module, "main") == 0) { if (strcmp(className, "Buffer") == 0) { methods.allocate = C_bufferAllocate; methods.finalize = C_bufferFinalize; } else if (strcmp(className, "Curl") == 0) { methods.allocate = C_curlAllocate; } } return methods; } WrenForeignMethodFn bindForeignMethod( WrenVM* vm, const char* module, const char* className, bool isStatic, const char* signature) { if (strcmp(module, "main") == 0) { if (strcmp(className, "Buffer") == 0) { if (!isStatic && strcmp(signature, "value") == 0) return C_value; } else if (strcmp(className, "Curl") == 0) { if (!isStatic && strcmp(signature, "easySetOpt(_,_)") == 0) return C_easySetOpt; if (!isStatic && strcmp(signature, "easyPerform()") == 0) return C_easyPerform; if (!isStatic && strcmp(signature, "easyCleanup()") == 0) return C_easyCleanup; } } return NULL; } static void writeFn(WrenVM* vm, const char* text) { printf("%s", text); } void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) { switch (errorType) { case WREN_ERROR_COMPILE: printf("[%s line %d] [Error] %s\n", module, line, msg); break; case WREN_ERROR_STACK_TRACE: printf("[%s line %d] in %s\n", module, line, msg); break; case WREN_ERROR_RUNTIME: printf("[Runtime Error] %s\n", msg); break; } } char *readFile(const char *fileName) { FILE *f = fopen(fileName, "r"); fseek(f, 0, SEEK_END); long fsize = ftell(f); rewind(f); char *script = malloc(fsize + 1); fread(script, 1, fsize, f); fclose(f); script[fsize] = 0; return script; } static void loadModuleComplete(WrenVM* vm, const char* module, WrenLoadModuleResult result) { if( result.source) free((void*)result.source); } WrenLoadModuleResult loadModule(WrenVM* vm, const char* name) { WrenLoadModuleResult result = {0}; if (strcmp(name, "random") != 0 && strcmp(name, "meta") != 0) { result.onComplete = loadModuleComplete; char fullName[strlen(name) + 6]; strcpy(fullName, name); strcat(fullName, ".wren"); result.source = readFile(fullName); } return result; } int main(int argc, char **argv) { WrenConfiguration config; wrenInitConfiguration(&config); config.writeFn = &writeFn; config.errorFn = &errorFn; config.bindForeignClassFn = &bindForeignClass; config.bindForeignMethodFn = &bindForeignMethod; config.loadModuleFn = &loadModule; WrenVM* vm = wrenNewVM(&config); const char* module = "main"; const char* fileName = "rc_count_examples.wren"; char *script = readFile(fileName); WrenInterpretResult result = wrenInterpret(vm, module, script); switch (result) { case WREN_RESULT_COMPILE_ERROR: printf("Compile Error!\n"); break; case WREN_RESULT_RUNTIME_ERROR: printf("Runtime Error!\n"); break; case WREN_RESULT_SUCCESS: break; } wrenFreeVM(vm); free(script); return 0; }
extern crate reqwest; extern crate url; extern crate rustc_serialize; use std::io::Read; use self::url::Url; use rustc_serialize::json::{self, Json}; pub struct Task { page_id: u64, pub title: String, } #[derive(Debug)] enum ParseError { Http(reqwest::Error), Json(json::ParserError), UnexpectedFormat, } impl From<json::ParserError> for ParseError { fn from(error: json::ParserError) -> Self { ParseError::Json(error) } } impl From<reqwest::Error> for ParseError { fn from(error: reqwest::Error) -> Self { ParseError::Http(error) } } fn construct_query_category(category: &str) -> Url { let mut base_url = Url::parse("http: let cat = format!("Category:{}", category); let query_pairs = vec![("action", "query"), ("format", "json"), ("list", "categorymembers"), ("cmlimit", "500"), ("cmtitle", &cat), ("continue", "")]; base_url.query_pairs_mut().extend_pairs(query_pairs.into_iter()); base_url } fn construct_query_task_content(task_id: &str) -> Url { let mut base_url = Url::parse("http: let mut query_pairs = vec![("action", "query"), ("format", "json"), ("prop", "revisions"), ("rvprop", "content")]; query_pairs.push(("pageids", task_id)); base_url.query_pairs_mut().extend_pairs(query_pairs.into_iter()); base_url } fn query_api(url: Url) -> Result<Json, ParseError> { let mut response = try!(reqwest::get(url.as_str())); let mut body = String::new(); response.read_to_string(&mut body).unwrap(); Ok(try!(Json::from_str(&body))) } fn parse_all_tasks(reply: &Json) -> Result<Vec<Task>, ParseError> { let json_to_task = |json: &Json| -> Result<Task, ParseError> { let page_id: u64 = try!(json.find("pageid") .and_then(|id| id.as_u64()) .ok_or(ParseError::UnexpectedFormat)); let title: &str = try!(json.find("title") .and_then(|title| title.as_string()) .ok_or(ParseError::UnexpectedFormat)); Ok(Task { page_id: page_id, title: title.to_owned(), }) }; let tasks_json = try!(reply.find_path(&["query", "categorymembers"]) .and_then(|tasks| tasks.as_array()) .ok_or(ParseError::UnexpectedFormat)); tasks_json.iter().map(json_to_task).collect() } fn count_number_examples(task: &Json, task_id: u64) -> Result<u32, ParseError> { let revisions = try!(task.find_path(&["query", "pages", task_id.to_string().as_str(), "revisions"]) .and_then(|content| content.as_array()) .ok_or(ParseError::UnexpectedFormat)); let content = try!(revisions[0] .find("*") .and_then(|content| content.as_string()) .ok_or(ParseError::UnexpectedFormat)); Ok(content.split("=={{header").count() as u32) } pub fn query_all_tasks() -> Vec<Task> { let query = construct_query_category("Programming_Tasks"); let json: Json = query_api(query).unwrap(); parse_all_tasks(&json).unwrap() } pub fn query_a_task(task: &Task) -> u32 { let query = construct_query_task_content(&task.page_id.to_string()); let json: Json = query_api(query).unwrap(); count_number_examples(&json, task.page_id).unwrap() }
Rosetta Code_Find unimplemented tasks
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <curl/curl.h> #include "wren.h" struct MemoryStruct { char *memory; size_t size; }; static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) { size_t realsize = size * nmemb; struct MemoryStruct *mem = (struct MemoryStruct *)userp; char *ptr = realloc(mem->memory, mem->size + realsize + 1); if(!ptr) { printf("not enough memory (realloc returned NULL)\n"); return 0; } mem->memory = ptr; memcpy(&(mem->memory[mem->size]), contents, realsize); mem->size += realsize; mem->memory[mem->size] = 0; return realsize; } void C_bufferAllocate(WrenVM* vm) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenSetSlotNewForeign(vm, 0, 0, sizeof(struct MemoryStruct)); ms->memory = malloc(1); ms->size = 0; } void C_bufferFinalize(void* data) { struct MemoryStruct *ms = (struct MemoryStruct *)data; free(ms->memory); } void C_curlAllocate(WrenVM* vm) { CURL** pcurl = (CURL**)wrenSetSlotNewForeign(vm, 0, 0, sizeof(CURL*)); *pcurl = curl_easy_init(); } void C_value(WrenVM* vm) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenGetSlotForeign(vm, 0); wrenSetSlotString(vm, 0, ms->memory); } void C_easyPerform(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); curl_easy_perform(curl); } void C_easyCleanup(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); curl_easy_cleanup(curl); } void C_easySetOpt(WrenVM* vm) { CURL* curl = *(CURL**)wrenGetSlotForeign(vm, 0); CURLoption opt = (CURLoption)wrenGetSlotDouble(vm, 1); if (opt < 10000) { long lparam = (long)wrenGetSlotDouble(vm, 2); curl_easy_setopt(curl, opt, lparam); } else if (opt < 20000) { if (opt == CURLOPT_WRITEDATA) { struct MemoryStruct *ms = (struct MemoryStruct *)wrenGetSlotForeign(vm, 2); curl_easy_setopt(curl, opt, (void *)ms); } else if (opt == CURLOPT_URL) { const char *url = wrenGetSlotString(vm, 2); curl_easy_setopt(curl, opt, url); } } else if (opt < 30000) { if (opt == CURLOPT_WRITEFUNCTION) { curl_easy_setopt(curl, opt, &WriteMemoryCallback); } } } WrenForeignClassMethods bindForeignClass(WrenVM* vm, const char* module, const char* className) { WrenForeignClassMethods methods; methods.allocate = NULL; methods.finalize = NULL; if (strcmp(module, "main") == 0) { if (strcmp(className, "Buffer") == 0) { methods.allocate = C_bufferAllocate; methods.finalize = C_bufferFinalize; } else if (strcmp(className, "Curl") == 0) { methods.allocate = C_curlAllocate; } } return methods; } WrenForeignMethodFn bindForeignMethod( WrenVM* vm, const char* module, const char* className, bool isStatic, const char* signature) { if (strcmp(module, "main") == 0) { if (strcmp(className, "Buffer") == 0) { if (!isStatic && strcmp(signature, "value") == 0) return C_value; } else if (strcmp(className, "Curl") == 0) { if (!isStatic && strcmp(signature, "easySetOpt(_,_)") == 0) return C_easySetOpt; if (!isStatic && strcmp(signature, "easyPerform()") == 0) return C_easyPerform; if (!isStatic && strcmp(signature, "easyCleanup()") == 0) return C_easyCleanup; } } return NULL; } static void writeFn(WrenVM* vm, const char* text) { printf("%s", text); } void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) { switch (errorType) { case WREN_ERROR_COMPILE: printf("[%s line %d] [Error] %s\n", module, line, msg); break; case WREN_ERROR_STACK_TRACE: printf("[%s line %d] in %s\n", module, line, msg); break; case WREN_ERROR_RUNTIME: printf("[Runtime Error] %s\n", msg); break; } } char *readFile(const char *fileName) { FILE *f = fopen(fileName, "r"); fseek(f, 0, SEEK_END); long fsize = ftell(f); rewind(f); char *script = malloc(fsize + 1); fread(script, 1, fsize, f); fclose(f); script[fsize] = 0; return script; } static void loadModuleComplete(WrenVM* vm, const char* module, WrenLoadModuleResult result) { if( result.source) free((void*)result.source); } WrenLoadModuleResult loadModule(WrenVM* vm, const char* name) { WrenLoadModuleResult result = {0}; if (strcmp(name, "random") != 0 && strcmp(name, "meta") != 0) { result.onComplete = loadModuleComplete; char fullName[strlen(name) + 6]; strcpy(fullName, name); strcat(fullName, ".wren"); result.source = readFile(fullName); } return result; } int main(int argc, char **argv) { WrenConfiguration config; wrenInitConfiguration(&config); config.writeFn = &writeFn; config.errorFn = &errorFn; config.bindForeignClassFn = &bindForeignClass; config.bindForeignMethodFn = &bindForeignMethod; config.loadModuleFn = &loadModule; WrenVM* vm = wrenNewVM(&config); const char* module = "main"; const char* fileName = "rc_find_unimplemented_tasks.wren"; char *script = readFile(fileName); WrenInterpretResult result = wrenInterpret(vm, module, script); switch (result) { case WREN_RESULT_COMPILE_ERROR: printf("Compile Error!\n"); break; case WREN_RESULT_RUNTIME_ERROR: printf("Runtime Error!\n"); break; case WREN_RESULT_SUCCESS: break; } wrenFreeVM(vm); free(script); return 0; }
use std::collections::{BTreeMap, HashSet}; use reqwest::Url; use serde::Deserialize; use serde_json::Value; #[derive(Clone, PartialEq, Eq, Hash, Debug, Deserialize)] pub struct Task { #[serde(rename = "pageid")] pub id: u64, pub title: String, } #[derive(Debug)] enum TaskParseError { Http(reqwest::Error), Json(serde_json::Error), UnexpectedFormat, } impl From<serde_json::Error> for TaskParseError { fn from(err: serde_json::Error) -> Self { TaskParseError::Json(err) } } impl From<reqwest::Error> for TaskParseError { fn from(err: reqwest::Error) -> Self { TaskParseError::Http(err) } } struct Category { name: String, continue_params: Option<BTreeMap<String, String>>, } impl Category { fn new(name: &str) -> Category { let mut continue_params = BTreeMap::new(); continue_params.insert("continue".to_owned(), "".to_owned()); Category { name: name.to_owned(), continue_params: Some(continue_params), } } } fn query_api( category_name: &str, continue_params: &BTreeMap<String, String>, ) -> Result<Value, TaskParseError> { let mut url = Url::parse("http: url.query_pairs_mut() .append_pair("action", "query") .append_pair("list", "categorymembers") .append_pair("cmtitle", &format!("Category:{}", category_name)) .append_pair("cmlimit", "500") .append_pair("format", "json") .extend_pairs(continue_params); Ok(reqwest::blocking::get(url)?.json()?) } fn parse_tasks(json: &Value) -> Result<Vec<Task>, TaskParseError> { let tasks_json = json .pointer("/query/categorymembers") .and_then(Value::as_array) .ok_or(TaskParseError::UnexpectedFormat)?; tasks_json .iter() .map(|json| Task::deserialize(json).map_err(From::from)) .collect() } impl Iterator for Category { type Item = Vec<Task>; fn next(&mut self) -> Option<Self::Item> { self.continue_params.as_ref()?; query_api(&self.name, self.continue_params.as_ref()?) .and_then(|result| { self.continue_params = result .get("continue") .and_then(Value::as_object) .map(|continue_params| { continue_params .iter() .map(|(key, value)| { (key.to_owned(), value.as_str().unwrap().to_owned()) }) .collect() }); parse_tasks(&result) }) .map_err(|err| println!("Error parsing response: {:?}", err)) .ok() } } pub fn all_tasks() -> Vec<Task> { Category::new("Programming Tasks").flatten().collect() } pub fn unimplemented_tasks(lang: &str) -> Vec<Task> { let all_tasks = all_tasks().iter().cloned().collect::<HashSet<_>>(); let implemented_tasks = Category::new(lang).flatten().collect::<HashSet<_>>(); let mut unimplemented_tasks = all_tasks .difference(&implemented_tasks) .cloned() .collect::<Vec<Task>>(); unimplemented_tasks.sort_by(|a, b| a.title.cmp(&b.title)); unimplemented_tasks } fn main() { for task in find_unimplemented_tasks::unimplemented_tasks("Rust") { println!("{:6} {}", task.id, task.title); } }
Rot-13
#include <ctype.h> #include <limits.h> #include <stdio.h> #include <stdlib.h> static char rot13_table[UCHAR_MAX + 1]; static void init_rot13_table(void) { static const unsigned char upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; static const unsigned char lower[] = "abcdefghijklmnopqrstuvwxyz"; for (int ch = '\0'; ch <= UCHAR_MAX; ch++) { rot13_table[ch] = ch; } for (const unsigned char *p = upper; p[13] != '\0'; p++) { rot13_table[p[0]] = p[13]; rot13_table[p[13]] = p[0]; } for (const unsigned char *p = lower; p[13] != '\0'; p++) { rot13_table[p[0]] = p[13]; rot13_table[p[13]] = p[0]; } } static void rot13_file(FILE *fp) { int ch; while ((ch = fgetc(fp)) != EOF) { fputc(rot13_table[ch], stdout); } } int main(int argc, char *argv[]) { init_rot13_table(); if (argc > 1) { for (int i = 1; i < argc; i++) { FILE *fp = fopen(argv[i], "r"); if (fp == NULL) { perror(argv[i]); return EXIT_FAILURE; } rot13_file(fp); fclose(fp); } } else { rot13_file(stdin); } return EXIT_SUCCESS; }
fn rot13(string: &str) -> String { string.chars().map(|c| { match c { 'a'..='m' | 'A'..='M' => ((c as u8) + 13) as char, 'n'..='z' | 'N'..='Z' => ((c as u8) - 13) as char, _ => c } }).collect() } fn main () { assert_eq!(rot13("abc"), "nop"); }
Run-length encoding
#include <stdio.h> #include <stdlib.h> typedef struct stream_t stream_t, *stream; struct stream_t { int (*get)(stream); int (*put)(stream, int); }; typedef struct { int (*get)(stream); int (*put)(stream, int); char *string; int pos; } string_stream; typedef struct { int (*get)(stream); int (*put)(stream, int); FILE *fp; } file_stream; int sget(stream in) { int c; string_stream* s = (string_stream*) in; c = (unsigned char)(s->string[s->pos]); if (c == '\0') return -1; s->pos++; return c; } int sput(stream out, int c) { string_stream* s = (string_stream*) out; s->string[s->pos++] = (c == -1) ? '\0' : c; if (c == -1) s->pos = 0; return 0; } int file_put(stream out, int c) { file_stream *f = (file_stream*) out; return fputc(c, f->fp); } void output(stream out, unsigned char* buf, int len) { int i; out->put(out, 128 + len); for (i = 0; i < len; i++) out->put(out, buf[i]); } void encode(stream in, stream out) { unsigned char buf[256]; int len = 0, repeat = 0, end = 0, c; int (*get)(stream) = in->get; int (*put)(stream, int) = out->put; while (!end) { end = ((c = get(in)) == -1); if (!end) { buf[len++] = c; if (len <= 1) continue; } if (repeat) { if (buf[len - 1] != buf[len - 2]) repeat = 0; if (!repeat || len == 129 || end) { put(out, end ? len : len - 1); put(out, buf[0]); buf[0] = buf[len - 1]; len = 1; } } else { if (buf[len - 1] == buf[len - 2]) { repeat = 1; if (len > 2) { output(out, buf, len - 2); buf[0] = buf[1] = buf[len - 1]; len = 2; } continue; } if (len == 128 || end) { output(out, buf, len); len = 0; repeat = 0; } } } put(out, -1); } void decode(stream in, stream out) { int c, i, cnt; while (1) { c = in->get(in); if (c == -1) return; if (c > 128) { cnt = c - 128; for (i = 0; i < cnt; i++) out->put(out, in->get(in)); } else { cnt = c; c = in->get(in); for (i = 0; i < cnt; i++) out->put(out, c); } } } int main() { char buf[256]; string_stream str_in = { sget, 0, "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW", 0}; string_stream str_out = { sget, sput, buf, 0 }; file_stream file = { 0, file_put, stdout }; encode((stream)&str_in, (stream)&str_out); decode((stream)&str_out, (stream)&file); return 0; }
fn encode(s: &str) -> String { s.chars() .map(Some) .chain(std::iter::once(None)) .scan((0usize, '\0'), |(n, c), elem| match elem { Some(elem) if *n == 0 || *c == elem => { *n += 1; *c = elem; Some(String::new()) } Some(elem) => { let run = format!("{}{}", n, c); *n = 1; *c = elem; Some(run) } None => { Some(format!("{}{}", n, c)) } }) .collect() } fn decode(s: &str) -> String { s.chars() .fold((0usize, String::new()), |(n, text), c| { if c.is_ascii_digit() { ( n * 10 + c.to_digit(10).expect("invalid encoding") as usize, text, ) } else { (0, text + &format!("{}", c.to_string().repeat(n))) } }) .1 } fn main() { let text = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"; let encoded = encode(text); let decoded = decode(&encoded); println!("original: {}\n encoded: {}\n decoded: {}", text, encoded, decoded); assert_eq!(text, decoded); }
Runge-Kutta method
#include <stdio.h> #include <stdlib.h> #include <math.h> double rk4(double(*f)(double, double), double dx, double x, double y) { double k1 = dx * f(x, y), k2 = dx * f(x + dx / 2, y + k1 / 2), k3 = dx * f(x + dx / 2, y + k2 / 2), k4 = dx * f(x + dx, y + k3); return y + (k1 + 2 * k2 + 2 * k3 + k4) / 6; } double rate(double x, double y) { return x * sqrt(y); } int main(void) { double *y, x, y2; double x0 = 0, x1 = 10, dx = .1; int i, n = 1 + (x1 - x0)/dx; y = (double *)malloc(sizeof(double) * n); for (y[0] = 1, i = 1; i < n; i++) y[i] = rk4(rate, dx, x0 + dx * (i - 1), y[i-1]); printf("x\ty\trel. err.\n------------\n"); for (i = 0; i < n; i += 10) { x = x0 + dx * i; y2 = pow(x * x / 4 + 1, 2); printf("%g\t%g\t%g\n", x, y[i], y[i]/y2 - 1); } return 0; }
fn runge_kutta4(fx: &dyn Fn(f64, f64) -> f64, x: f64, y: f64, dx: f64) -> f64 { let k1 = dx * fx(x, y); let k2 = dx * fx(x + dx / 2.0, y + k1 / 2.0); let k3 = dx * fx(x + dx / 2.0, y + k2 / 2.0); let k4 = dx * fx(x + dx, y + k3); y + (k1 + 2.0 * k2 + 2.0 * k3 + k4) / 6.0 } fn f(x: f64, y: f64) -> f64 { x * y.sqrt() } fn actual(x: f64) -> f64 { (1.0 / 16.0) * (x * x + 4.0).powi(2) } fn main() { let mut y = 1.0; let mut x = 0.0; let step = 0.1; let max_steps = 101; let sample_every_n = 10; for steps in 0..max_steps { if steps % sample_every_n == 0 { println!("y({}):\t{:.10}\t\t {:E}", x, y, actual(x) - y) } y = runge_kutta4(&f, x, y, step); x = ((x * 10.0) + (step * 10.0)) / 10.0; } }
S-expressions
#include <stdio.h> #include <stdlib.h> #include <ctype.h> #include <string.h> enum { S_NONE, S_LIST, S_STRING, S_SYMBOL }; typedef struct { int type; size_t len; void *buf; } s_expr, *expr; void whine(const char *s) { fprintf(stderr, "parse error before ==>%.10s\n", s); } expr parse_string(const char *s, char **e) { expr ex = calloc(sizeof(s_expr), 1); char buf[256] = {0}; int i = 0; while (*s) { if (i >= 256) { fprintf(stderr, "string too long:\n"); whine(s); goto fail; } switch (*s) { case '\\': switch (*++s) { case '\\': case '"': buf[i++] = *s++; continue; default: whine(s); goto fail; } case '"': goto success; default: buf[i++] = *s++; } } fail: free(ex); return 0; success: *(const char **)e = s + 1; ex->type = S_STRING; ex->buf = strdup(buf); ex->len = strlen(buf); return ex; } expr parse_symbol(const char *s, char **e) { expr ex = calloc(sizeof(s_expr), 1); char buf[256] = {0}; int i = 0; while (*s) { if (i >= 256) { fprintf(stderr, "symbol too long:\n"); whine(s); goto fail; } if (isspace(*s)) goto success; if (*s == ')' || *s == '(') { s--; goto success; } switch (*s) { case '\\': switch (*++s) { case '\\': case '"': case '(': case ')': buf[i++] = *s++; continue; default: whine(s); goto fail; } case '"': whine(s); goto success; default: buf[i++] = *s++; } } fail: free(ex); return 0; success: *(const char **)e = s + 1; ex->type = S_SYMBOL; ex->buf = strdup(buf); ex->len = strlen(buf); return ex; } void append(expr list, expr ele) { list->buf = realloc(list->buf, sizeof(expr) * ++list->len); ((expr*)(list->buf))[list->len - 1] = ele; } expr parse_list(const char *s, char **e) { expr ex = calloc(sizeof(s_expr), 1), chld; char *next; ex->len = 0; while (*s) { if (isspace(*s)) { s++; continue; } switch (*s) { case '"': chld = parse_string(s+1, &next); if (!chld) goto fail; append(ex, chld); s = next; continue; case '(': chld = parse_list(s+1, &next); if (!chld) goto fail; append(ex, chld); s = next; continue; case ')': goto success; default: chld = parse_symbol(s, &next); if (!chld) goto fail; append(ex, chld); s = next; continue; } } fail: whine(s); free(ex); return 0; success: *(const char **)e = s+1; ex->type = S_LIST; return ex; } expr parse_term(const char *s, char **e) { while (*s) { if (isspace(*s)) { s++; continue; } switch(*s) { case '(': return parse_list(s+1, e); case '"': return parse_string(s+1, e); default: return parse_symbol(s+1, e); } } return 0; } void print_expr(expr e, int depth) { #define sep() for(i = 0; i < depth; i++) printf(" ") int i; if (!e) return; switch(e->type) { case S_LIST: sep(); puts("("); for (i = 0; i < e->len; i++) print_expr(((expr*)e->buf)[i], depth + 1); sep(); puts(")"); return; case S_SYMBOL: case S_STRING: sep(); if (e->type == S_STRING) putchar('"'); for (i = 0; i < e->len; i++) { switch(((char*)e->buf)[i]) { case '"': case '\\': putchar('\\'); break; case ')': case '(': if (e->type == S_SYMBOL) putchar('\\'); } putchar(((char*)e->buf)[i]); } if (e->type == S_STRING) putchar('"'); putchar('\n'); return; } } int main() { char *next; const char *in = "((data da\\(\\)ta \"quot\\\\ed data\" 123 4.5)\n" " (\"data\" (!@# (4.5) \"(mo\\\"re\" \"data)\")))"; expr x = parse_term(in, &next); printf("input is:\n%s\n", in); printf("parsed as:\n"); print_expr(x, 0); return 0; }
extern crate typed_arena; use typed_arena::Arena; use self::Error::*; use self::SExp::*; use self::Token::*; use std::io; use std::num::FpCategory; use std::str::FromStr; #[derive(PartialEq, Debug)] pub enum SExp<'a> { F64(f64), List(&'a [SExp<'a>]), Str(&'a str), } #[derive(PartialEq, Debug)] pub enum Error { NoReprForFloat, UnterminatedStringLiteral, Io, IncorrectCloseDelimiter, UnexpectedEOF, ExpectedEOF, } impl From<io::Error> for Error { fn from(_err: io::Error) -> Error { Error::Io } } #[derive(PartialEq, Debug)] enum Token<'a> { ListStart, ListEnd, Literal(SExp<'a>), Eof, } #[derive(Copy, Clone, Debug)] struct Tokens<'a> { string: &'a str, first: Option<char>, rest: &'a str, } impl<'a> Tokens<'a> { fn new(string: &str) -> Tokens { let mut chars = string.chars(); match chars.next() { Some(ch) => Tokens { string, first: Some(ch), rest: chars.as_str(), }, None => Tokens { string, first: None, rest: string, }, } } fn update(&mut self, string: &'a str) { self.string = string; let mut chars = self.string.chars(); if let Some(ch) = chars.next() { self.first = Some(ch); self.rest = chars.as_str(); } else { self.first = None; }; } fn next_token(&mut self) -> Result<Token<'a>, Error> { loop { match self.first { Some('(') => { self.update(self.rest); return Ok(ListStart); } Some(')') => { self.update(self.rest); return Ok(ListEnd); } Some('"') => { let mut iter = self.rest.splitn(2, '"'); let str = iter.next().unwrap(); match iter.next() { Some(s) => { self.update(s); return Ok(Literal(Str(str))); } None => return Err(UnterminatedStringLiteral), } } Some(c) => { if c.is_whitespace() { self.update(self.rest); continue; } let mut end_ch = None; let str = { let mut iter = self.string.splitn(2, |ch: char| { let term = ch == ')' || ch == '('; if term { end_ch = Some(ch) } term || ch.is_whitespace() }); let str = iter.next().unwrap(); self.rest = iter.next().unwrap_or(""); str }; match end_ch { Some(_) => self.first = end_ch, None => self.update(self.rest), } return Ok(Literal(parse_literal(str))); } None => return Ok(Eof), } } } } fn parse_literal(literal: &str) -> SExp { match literal.bytes().next() { Some(b'0'..=b'9') | Some(b'-') => match f64::from_str(literal) { Ok(f) => F64(f), Err(_) => Str(literal), }, _ => Str(literal), } } pub struct ParseContext<'a> { string: &'a str, arena: Option<Arena<Vec<SExp<'a>>>>, stack: Vec<Vec<SExp<'a>>>, } impl<'a> ParseContext<'a> { pub fn new(string: &'a str) -> ParseContext<'a> { ParseContext { string, arena: None, stack: Vec::new(), } } } impl<'a> SExp<'a> { fn encode<T: io::Write>(&self, writer: &mut T) -> Result<(), Error> { match *self { F64(f) => { match f.classify() { FpCategory::Normal | FpCategory::Zero => { write!(writer, "{}", f)?; Ok(()) } _ => Err(Error::NoReprForFloat), } } List(l) => { write!(writer, "(")?; let mut iter = l.iter(); if let Some(sexp) = iter.next() { sexp.encode(writer)?; for sexp in iter { write!(writer, " ")?; sexp.encode(writer)?; } } write!(writer, ")")?; Ok(()) } Str(s) => { write!(writer, "\"{}\"", s)?; Ok(()) } } } pub fn parse(ctx: &'a mut ParseContext<'a>) -> Result<SExp<'a>, Error> { ctx.arena = Some(Arena::new()); let arena = match ctx.arena { Some(ref mut arena) => arena, None => unreachable!(), }; let ParseContext { string, ref mut stack, .. } = *ctx; stack.clear(); let mut tokens = Tokens::new(string); let next = tokens.next_token(); let mut list = match next? { ListStart => Vec::new(), Literal(s) => { return if tokens.next_token()? == Eof { Ok(s) } else { Err(ExpectedEOF) }; } ListEnd => return Err(IncorrectCloseDelimiter), Eof => return Err(UnexpectedEOF), }; loop { let tok = tokens.next_token(); match tok? { ListStart => { stack.push(list); list = Vec::new() } Literal(s) => list.push(s), ListEnd => { match stack.pop() { Some(mut l) => { l.push(List(&*arena.alloc(list))); list = l; } None => { return match tokens.next_token()? { Eof => Ok(List(&*arena.alloc(list))), _ => Err(ExpectedEOF), }; } } } Eof => return Err(UnexpectedEOF), } } } pub fn buffer_encode(&self) -> Result<String, Error> { let mut m = Vec::new(); self.encode(&mut m)?; unsafe { Ok(String::from_utf8_unchecked(m)) } } } pub const SEXP_STRUCT: SExp<'static> = List(&[ List(&[Str("data"), Str("quoted data"), F64(123.), F64(4.5)]), List(&[ Str("data"), List(&[Str("!@#"), List(&[F64(4.5)]), Str("(more"), Str("data)")]), ]), ]); pub const SEXP_STRING_IN: &str = r#"((data "quoted data" 123 4.5) (data (!@# (4.5) "(more" "data)")))"#; and main.rs: use s_expressions::{ParseContext, SExp, SEXP_STRING_IN, SEXP_STRUCT}; fn main() { println!("{:?}", SEXP_STRUCT.buffer_encode()); let ctx = &mut ParseContext::new(SEXP_STRING_IN); println!("{:?}", SExp::parse(ctx)); }
SEDOLs
#include <stdio.h> #include <ctype.h> #include <string.h> int sedol_weights[] = {1, 3, 1, 7, 3, 9}; const char *reject = "AEIOUaeiou"; int sedol_checksum(const char *sedol6) { int len = strlen(sedol6); int sum = 0, i; if ( len == 7 ) { fprintf(stderr, "SEDOL code already checksummed? (%s)\n", sedol6); return sedol6[6] & 0x7f; } if ( (len > 7) || (len < 6) || ( strcspn(sedol6, reject) != 6 )) { fprintf(stderr, "not a SEDOL code? (%s)\n", sedol6); return -1; } for(i=0; i < 6; i++) { if ( isdigit(sedol6[i]) ) { sum += (sedol6[i]-'0')*sedol_weights[i]; } else if ( isalpha(sedol6[i]) ) { sum += ((toupper(sedol6[i])-'A') + 10)*sedol_weights[i]; } else { fprintf(stderr, "SEDOL with not alphanumeric digit\n"); return -1; } } return (10 - (sum%10))%10 + '0'; } #define MAXLINELEN 10 int main() { char line[MAXLINELEN]; int sr, len; while( fgets(line, MAXLINELEN, stdin) != NULL ) { len = strlen(line); if ( line[len-1] == '\n' ) line[len-1]='\0'; sr = sedol_checksum(line); if ( sr > 0 ) printf("%s%c\n", line, sr); } return 0; }
fn sedol(input: &str) -> Option<String> { let weights = vec![1, 3, 1, 7, 3, 9, 1]; let valid_chars = "0123456789BCDFGHJKLMNPQRSTVWXYZ"; if input.len() != 6 { return None; } for c in input.chars() { if !valid_chars.contains(c) { return None; } } let mut result: u32 = input .chars() .map(|c| { if c.is_digit(10) { c as u32 - 48 } else { c as u32 - 55 } }) .zip(weights) .map(|(cnum, w)| w * cnum) .collect::<Vec<u32>>() .iter() .sum(); result = (10 - result % 10) % 10; Some(input.to_owned() + &result.to_string()) } fn main() { let inputs = vec![ "710889", "B0YBKJ", "406566", "B0YBLH", "228276", "B0YBKL", "557910", "B0YBKR", "585284", "B0YBKT", "B00030", ]; for input in inputs { println!("{} SEDOL: {:?}", &input, sedol(&input).unwrap()); } }
SHA-1
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <openssl/sha.h> int main() { int i; unsigned char result[SHA_DIGEST_LENGTH]; const char *string = "Rosetta Code"; SHA1(string, strlen(string), result); for(i = 0; i < SHA_DIGEST_LENGTH; i++) printf("%02x%c", result[i], i < (SHA_DIGEST_LENGTH-1) ? ' ' : '\n'); return EXIT_SUCCESS; }
use sha1::Sha1; fn main() { let mut hash_msg = Sha1::new(); hash_msg.update(b"Rosetta Code"); println!("{}", hash_msg.digest().to_string()); }
SHA-256
#include <stdio.h> #include <string.h> #include <openssl/sha.h> int main (void) { const char *s = "Rosetta code"; unsigned char *d = SHA256(s, strlen(s), 0); int i; for (i = 0; i < SHA256_DIGEST_LENGTH; i++) printf("%02x", d[i]); putchar('\n'); return 0; }
use sha2::{Digest, Sha256}; fn hex_string(input: &[u8]) -> String { input.as_ref().iter().map(|b| format!("{:x}", b)).collect() } fn main() { let mut hasher = Sha256::new(); hasher.update(b"Rosetta code"); let result = hasher.finalize(); let hex = hex_string(&result); assert_eq!( hex, "764faf5c61ac315f1497f9dfa542713965b785e5cc2f707d6468d7d1124cdfcf" ); println!("{}", hex); }
Search a list
#include <stdio.h> #include <string.h> const char *haystack[] = { "Zig", "Zag", "Wally", "Ronald", "Bush", "Krusty", "Charlie", "Bush", "Boz", "Zag", NULL }; int search_needle(const char *needle, const char **hs) { int i = 0; while( hs[i] != NULL ) { if ( strcmp(hs[i], needle) == 0 ) return i; i++; } return -1; } int search_last_needle(const char *needle, const char **hs) { int i, last=0; i = last = search_needle(needle, hs); if ( last < 0 ) return -1; while( hs[++i] != NULL ) { if ( strcmp(needle, hs[i]) == 0 ) { last = i; } } return last; } int main() { printf("Bush is at %d\n", search_needle("Bush", haystack)); if ( search_needle("Washington", haystack) == -1 ) printf("Washington is not in the haystack\n"); printf("First index for Zag: %d\n", search_needle("Zag", haystack)); printf("Last index for Zag: %d\n", search_last_needle("Zag", haystack)); return 0; }
fn main() { let haystack=vec!["Zig", "Zag", "Wally", "Ronald", "Bush", "Krusty", "Charlie", "Bush", "Boz", "Zag"]; println!("First occurence of 'Bush' at {:?}",haystack.iter().position(|s| *s=="Bush")); println!("Last occurence of 'Bush' at {:?}",haystack.iter().rposition(|s| *s=="Bush")); println!("First occurence of 'Rob' at {:?}",haystack.iter().position(|s| *s=="Rob")); }
Secure temporary file
#include <stdlib.h> #include <stdio.h> int main(void) { FILE *fh = tmpfile(); fclose(fh); return 0; }
use tempfile::tempfile; fn main() { let fh = tempfile(); println!("{:?}", fh); }
Semiprime
#include <stdio.h> int semiprime(int n) { int p, f = 0; for (p = 2; f < 2 && p*p <= n; p++) while (0 == n % p) n /= p, f++; return f + (n > 1) == 2; } int main(void) { int i; for (i = 2; i < 100; i++) if (semiprime(i)) printf(" %d", i); putchar('\n'); return 0; }
extern crate primal; fn isqrt(n: usize) -> usize { (n as f64).sqrt() as usize } fn is_semiprime(mut n: usize) -> bool { let root = isqrt(n) + 1; let primes1 = primal::Sieve::new(root); let mut count = 0; for i in primes1.primes_from(2).take_while(|&x| x < root) { while n % i == 0 { n /= i; count += 1; } if n == 1 { break; } } if n != 1 { count += 1; } count == 2 } #[test] fn test1() { assert_eq!((2..10).filter(|&n| is_semiprime(n)).count(), 3); } #[test] fn test2() { assert_eq!((2..100).filter(|&n| is_semiprime(n)).count(), 34); } #[test] fn test3() { assert_eq!((2..1_000).filter(|&n| is_semiprime(n)).count(), 299); } #[test] fn test4() { assert_eq!((2..10_000).filter(|&n| is_semiprime(n)).count(), 2_625); } #[test] fn test5() { assert_eq!((2..100_000).filter(|&n| is_semiprime(n)).count(), 23_378); } #[test] fn test6() { assert_eq!((2..1_000_000).filter(|&n| is_semiprime(n)).count(), 210_035); }
Semordnilap
#include <stdio.h> #include <stdlib.h> #include <alloca.h> #include <string.h> static void reverse(char *s, int len) { int i, j; char tmp; for (i = 0, j = len - 1; i < len / 2; ++i, --j) tmp = s[i], s[i] = s[j], s[j] = tmp; } static int strsort(const void *s1, const void *s2) { return strcmp(*(char *const *) s1, *(char *const *) s2); } int main(void) { int i, c, ct = 0, len, sem = 0; char **words, **drows, tmp[24]; FILE *dict = fopen("unixdict.txt", "r"); while ((c = fgetc(dict)) != EOF) ct += c == '\n'; rewind(dict); words = alloca(ct * sizeof words); drows = alloca(ct * sizeof drows); for (i = 0; fscanf(dict, "%s%n", tmp, &len) != EOF; ++i) { strcpy(words[i] = alloca(len), tmp); strcpy(drows[i] = alloca(len), tmp); reverse(drows[i], len - 1); } fclose(dict); qsort(drows, ct, sizeof drows, strsort); for (c = i = 0; i < ct; ++i) { while (strcmp(drows[i], words[c]) > 0 && c < ct - 1) c++; if (!strcmp(drows[i], words[c])) { strcpy(tmp, drows[i]); reverse(tmp, strlen(tmp)); if (strcmp(drows[i], tmp) > 0 && sem++ < 5) printf("%s\t%s\n", drows[i], tmp); } } printf("Semordnilap pairs: %d\n", sem); return 0; }
use std::collections::HashSet; use std::fs::File; use std::io::{self, BufRead}; use std::iter::FromIterator; fn semordnilap(filename: &str) -> std::io::Result<()> { let file = File::open(filename)?; let mut seen = HashSet::new(); let mut count = 0; for line in io::BufReader::new(file).lines() { let mut word = line?; word.make_ascii_lowercase(); let rev = String::from_iter(word.chars().rev()); if seen.contains(&rev) { if count < 5 { println!("{}\t{}", word, rev); } count += 1; } else { seen.insert(word); } } println!("\nSemordnilap pairs found: {}", count); Ok(()) } fn main() { match semordnilap("unixdict.txt") { Ok(()) => {} Err(error) => eprintln!("{}", error), } }
Sequence of non-squares
#include <math.h> #include <stdio.h> #include <assert.h> int nonsqr(int n) { return n + (int)(0.5 + sqrt(n)); } int main() { int i; for (i = 1; i < 23; i++) printf("%d ", nonsqr(i)); printf("\n"); for (i = 1; i < 1000000; i++) { double j = sqrt(nonsqr(i)); assert(j != floor(j)); } return 0; }
fn f(n: i64) -> i64 { n + (0.5 + (n as f64).sqrt()) as i64 } fn is_sqr(n: i64) -> bool { let a = (n as f64).sqrt() as i64; n == a * a || n == (a+1) * (a+1) || n == (a-1) * (a-1) } fn main() { println!( "{:?}", (1..23).map(|n| f(n)).collect::<Vec<i64>>() ); let count = (1..1_000_000).map(|n| f(n)).filter(|&n| is_sqr(n)).count(); println!("{} unexpected squares found", count); }
Sequence of primes by trial division
#include<stdio.h> int isPrime(unsigned int n) { unsigned int num; if ( n < 2||!(n & 1)) return n == 2; for (num = 3; num <= n/num; num += 2) if (!(n % num)) return 0; return 1; } int main() { unsigned int l,u,i,sum=0; printf("Enter lower and upper bounds: "); scanf("%ld%ld",&l,&u); for(i=l;i<=u;i++){ if(isPrime(i)==1) { printf("\n%ld",i); sum++; } } printf("\n\nPrime numbers found in [%ld,%ld] : %ld",l,u,sum); return 0; }
fn is_prime(number: u32) -> bool { #[allow(clippy::cast_precision_loss)] let limit = (number as f32).sqrt() as u32 + 1; !(number < 2 || (2..limit).any(|x| number % x == 0)) } fn main() { println!( "Primes below 100:\n{:?}", (0_u32..100).fold(vec![], |mut acc, number| { if is_prime(number) { acc.push(number) }; acc }) ); }
Set
#include <stdio.h> typedef unsigned int set_t; void show_set(set_t x, const char *name) { int i; printf("%s is:", name); for (i = 0; (1U << i) <= x; i++) if (x & (1U << i)) printf(" %d", i); putchar('\n'); } int main(void) { int i; set_t a, b, c; a = 0; for (i = 0; i < 10; i += 3) a |= (1U << i); show_set(a, "a"); for (i = 0; i < 5; i++) printf("\t%d%s in set a\n", i, (a & (1U << i)) ? "":" not"); b = a; b |= (1U << 5); b |= (1U << 10); b &= ~(1U << 0); show_set(b, "b"); show_set(a | b, "union(a, b)"); show_set(c = a & b, "c = common(a, b)"); show_set(a & ~b, "a - b"); show_set(b & ~a, "b - a"); printf("b is%s a subset of a\n", !(b & ~a) ? "" : " not"); printf("c is%s a subset of a\n", !(c & ~a) ? "" : " not"); printf("union(a, b) - common(a, b) %s union(a - b, b - a)\n", ((a | b) & ~(a & b)) == ((a & ~b) | (b & ~a)) ? "equals" : "does not equal"); return 0; }
use std::collections::HashSet; fn main() { let a = vec![1, 3, 4].into_iter().collect::<HashSet<i32>>(); let b = vec![3, 5, 6].into_iter().collect::<HashSet<i32>>(); println!("Set A: {:?}", a.iter().collect::<Vec<_>>()); println!("Set B: {:?}", b.iter().collect::<Vec<_>>()); println!("Does A contain 4? {}", a.contains(&4)); println!("Union: {:?}", a.union(&b).collect::<Vec<_>>()); println!("Intersection: {:?}", a.intersection(&b).collect::<Vec<_>>()); println!("Difference: {:?}", a.difference(&b).collect::<Vec<_>>()); println!("Is A a subset of B? {}", a.is_subset(&b)); println!("Is A equal to B? {}", a == b); }
Set puzzle
#include <stdio.h> #include <stdlib.h> char *names[4][3] = { { "red", "green", "purple" }, { "oval", "squiggle", "diamond" }, { "one", "two", "three" }, { "solid", "open", "striped" } }; int set[81][81]; void init_sets(void) { int i, j, t, a, b; for (i = 0; i < 81; i++) { for (j = 0; j < 81; j++) { for (t = 27; t; t /= 3) { a = (i / t) % 3; b = (j / t) % 3; set[i][j] += t * (a == b ? a : 3 - a - b); } } } } void deal(int *out, int n) { int i, j, t, c[81]; for (i = 0; i < 81; i++) c[i] = i; for (i = 0; i < n; i++) { j = i + (rand() % (81 - i)); t = c[i], c[i] = out[i] = c[j], c[j] = t; } } int get_sets(int *cards, int n, int sets[][3]) { int i, j, k, s = 0; for (i = 0; i < n; i++) { for (j = i + 1; j < n; j++) { for (k = j + 1; k < n; k++) { if (set[cards[i]][cards[j]] == cards[k]) sets[s][0] = i, sets[s][1] = j, sets[s][2] = k, s++; } } } return s; } void show_card(int c) { int i, t; for (i = 0, t = 27; t; i++, t /= 3) printf("%9s", names[i][(c/t)%3]); putchar('\n'); } void deal_sets(int ncard, int nset) { int c[81]; int csets[81][3]; int i, j, s; do deal(c, ncard); while ((s = get_sets(c, ncard, csets)) != nset); printf("dealt %d cards\n", ncard); for (i = 0; i < ncard; i++) { printf("%2d:", i); show_card(c[i]); } printf("\nsets:\n"); for (i = 0; i < s; i++) { for (j = 0; j < 3; j++) { printf("%2d:", csets[i][j]); show_card(c[csets[i][j]]); } putchar('\n'); } } int main(void) { init_sets(); deal_sets(9, 4); while (1) deal_sets(12, 6); return 0; }
use itertools::Itertools; use rand::Rng; const DECK_SIZE: usize = 81; const NUM_ATTRIBUTES: usize = 4; const ATTRIBUTES: [&[&str]; NUM_ATTRIBUTES] = [ &["red", "green", "purple"], &["one", "two", "three"], &["oval", "squiggle", "diamond"], &["solid", "open", "striped"], ]; fn get_random_card_indexes(num_of_cards: usize) -> Vec<usize> { let mut selected_cards: Vec<usize> = Vec::with_capacity(num_of_cards); let mut rng = rand::thread_rng(); loop { let idx = rng.gen_range(0..DECK_SIZE); if !selected_cards.contains(&idx) { selected_cards.push(idx); } if selected_cards.len() == num_of_cards { break; } } selected_cards } fn run_game(num_of_cards: usize, minimum_number_of_sets: usize) { println!( "\nGAME: # of cards: {} # of sets: {}", num_of_cards, minimum_number_of_sets ); let deck = (0..NUM_ATTRIBUTES) .map(|_| (0..=2_usize)) .multi_cartesian_product() .collect::<Vec<_>>(); let valid_attribute = |a: usize, b: usize, c: usize| -> bool { a == b && b == c || (a != b && b != c && a != c) }; let valid_set = |t: &Vec<&Vec<usize>>| -> bool { for attr in 0..NUM_ATTRIBUTES { if !valid_attribute(t[0][attr], t[1][attr], t[2][attr]) { return false; } } true }; loop { let selected_cards = get_random_card_indexes(num_of_cards) .iter() .map(|idx| deck[*idx].clone()) .collect::<Vec<_>>(); let valid_sets = selected_cards .iter() .combinations(3) .filter(|triplet| valid_set(triplet)) .collect::<Vec<_>>(); if valid_sets.len() == minimum_number_of_sets { print!("SELECTED CARDS:"); for card in &selected_cards { print!("\ncard: "); for attr in 0..NUM_ATTRIBUTES { print!("{}, ", ATTRIBUTES[attr][card[attr]]); } } print!("\nSets:"); for triplet in &valid_sets { print!("\nSet: "); for card in triplet { for attr in 0..NUM_ATTRIBUTES { print!("{}, ", ATTRIBUTES[attr][card[attr]]); } print!(" | "); } } break; } } } fn main() { run_game(9, 4); run_game(12, 6); }
Short-circuit evaluation
#include <stdio.h> #include <stdbool.h> bool a(bool in) { printf("I am a\n"); return in; } bool b(bool in) { printf("I am b\n"); return in; } #define TEST(X,Y,O) \ do { \ x = a(X) O b(Y); \ printf(#X " " #O " " #Y " = %s\n\n", x ? "true" : "false"); \ } while(false); int main() { bool x; TEST(false, true, &&); TEST(true, false, ||); TEST(true, false, &&); TEST(false, false, ||); return 0; }
fn a(foo: bool) -> bool { println!("a"); foo } fn b(foo: bool) -> bool { println!("b"); foo } fn main() { for i in vec![true, false] { for j in vec![true, false] { println!("{} and {} == {}", i, j, a(i) && b(j)); println!("{} or {} == {}", i, j, a(i) || b(j)); println!(); } } }
Show ASCII table
#include <stdio.h> int main() { int i, j; char k[4]; for (i = 0; i < 16; ++i) { for (j = 32 + i; j < 128; j += 16) { switch (j) { default: sprintf(k, "%c", j); break; case 32: sprintf(k, "Spc"); break; case 127: sprintf(k, "Del"); break; } printf("%3d : %-3s ", j, k); } printf("\n"); } return 0; }
fn main() { for i in 0u8..16 { for j in ((32+i)..128).step_by(16) { let k = (j as char).to_string(); print!("{:3} : {:<3} ", j, match j { 32 => "Spc", 127 => "Del", _ => &k, }); } println!(); } }
Show the (decimal) value of a number of 1s appended with a 3, then squared
#include <stdio.h> #include <stdint.h> uint64_t ones_plus_three(uint64_t ones) { uint64_t r = 0; while (ones--) r = r*10 + 1; return r*10 + 3; } int main() { uint64_t n; for (n=0; n<8; n++) { uint64_t x = ones_plus_three(n); printf("%8lu^2 = %15lu\n", x, x*x); } return 0; }
fn main() { let mut big_squares : Vec<u64> = Vec::new( ) ; let mut numberstrings : Vec<String> = Vec::new( ) ; for n in 0..8 { let mut numberstring : String = String::new( ) ; for i in 0..=n { if i != 0 { numberstring.push( '1' ) ; } } numberstring.push('3') ; let number : u64 = numberstring.parse::<u64>().unwrap( ) ; numberstrings.push( numberstring ) ; big_squares.push( number.pow( 2 )) ; } for i in 0..numberstrings.len( ) { print!("{} ^ 2 =" , numberstrings[ i ] ) ; let width = 30 - (7 + i ) ; println!("{:>width$}" , big_squares[ i ] ) ; } }
Show the epoch
#include <time.h> #include <stdio.h> int main() { time_t t = 0; printf("%s", asctime(gmtime(&t))); return 0; }
extern crate time; use time::{at_utc, Timespec}; fn main() { let epoch = at_utc(Timespec::new(0, 0)); println!("{}", epoch.asctime()); }
Sierpinski carpet
#include <stdio.h> int main() { int i, j, dim, d; int depth = 3; for (i = 0, dim = 1; i < depth; i++, dim *= 3); for (i = 0; i < dim; i++) { for (j = 0; j < dim; j++) { for (d = dim / 3; d; d /= 3) if ((i % (d * 3)) / d == 1 && (j % (d * 3)) / d == 1) break; printf(d ? " " : "##"); } printf("\n"); } return 0; }
fn main() { for i in 0..4 { println!("\nN={}", i); println!("{}", sierpinski_carpet(i)); } } fn sierpinski_carpet(n: u32) -> String { let mut carpet = vec!["#".to_string()]; for _ in 0..n { let mut top: Vec<_> = carpet.iter().map(|x| x.repeat(3)).collect(); let middle: Vec<_> = carpet .iter() .map(|x| x.to_string() + &x.replace("#", " ") + x) .collect(); let bottom = top.clone(); top.extend(middle); top.extend(bottom); carpet = top; } carpet.join("\n") }
Sierpinski triangle
#include <stdio.h> #define SIZE (1 << 4) int main() { int x, y, i; for (y = SIZE - 1; y >= 0; y--, putchar('\n')) { for (i = 0; i < y; i++) putchar(' '); for (x = 0; x + y < SIZE; x++) printf((x & y) ? " " : "* "); } return 0; }
use std::iter::repeat; fn sierpinski(order: usize) { let mut triangle = vec!["*".to_string()]; for i in 0..order { let space = repeat(' ').take(2_usize.pow(i as u32)).collect::<String>(); let mut d = triangle.clone(); d.iter_mut().for_each(|r| { let new_row = format!("{}{}{}", space, r, space); *r = new_row; }); triangle.iter().for_each(|r| { let new_row = format!("{}{}{}", r, " ", r); d.push(new_row); }); triangle = d; } triangle.iter().for_each(|r| println!("{}", r)); } fn main() { let order = std::env::args() .nth(1) .unwrap_or_else(|| "4".to_string()) .parse::<usize>() .unwrap(); sierpinski(order); }
Sieve of Eratosthenes
#include <stdlib.h> #include <math.h> char* eratosthenes(int n, int *c) { char* sieve; int i, j, m; if(n < 2) return NULL; *c = n-1; m = (int) sqrt((double) n); sieve = calloc(n+1,sizeof(char)); sieve[0] = 1; sieve[1] = 1; for(i = 2; i <= m; i++) if(!sieve[i]) for (j = i*i; j <= n; j += i) if(!sieve[j]){ sieve[j] = 1; --(*c); } return sieve; }
fn primes(n: usize) -> impl Iterator<Item = usize> { const START: usize = 2; if n < START { Vec::new() } else { let mut is_prime = vec![true; n + 1 - START]; let limit = (n as f64).sqrt() as usize; for i in START..limit + 1 { let mut it = is_prime[i - START..].iter_mut().step_by(i); if let Some(true) = it.next() { it.for_each(|x| *x = false); } } is_prime } .into_iter() .enumerate() .filter_map(|(e, b)| if b { Some(e + START) } else { None }) }
Simple windowed application
#include <stdio.h> #include <gtk/gtk.h> const gchar *clickme = "Click Me"; guint counter = 0; #define MAXLEN 64 void clickedme(GtkButton *o, gpointer d) { GtkLabel *l = GTK_LABEL(d); char nt[MAXLEN]; counter++; snprintf(nt, MAXLEN, "You clicked me %d times", counter); gtk_label_set_text(l, nt); } int main(int argc, char **argv) { GtkWindow *win; GtkButton *button; GtkLabel *label; GtkVBox *vbox; gtk_init(&argc, &argv); win = (GtkWindow*)gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_window_set_title(win, clickme); button = (GtkButton*)gtk_button_new_with_label(clickme); label = (GtkLabel*)gtk_label_new("There have been no clicks yet"); gtk_label_set_single_line_mode(label, TRUE); vbox = (GtkVBox*)gtk_vbox_new(TRUE, 1); gtk_container_add(GTK_CONTAINER(vbox), GTK_WIDGET(label)); gtk_container_add(GTK_CONTAINER(vbox), GTK_WIDGET(button)); gtk_container_add(GTK_CONTAINER(win), GTK_WIDGET(vbox)); g_signal_connect(G_OBJECT(win), "delete-event", (GCallback)gtk_main_quit, NULL); g_signal_connect(G_OBJECT(button), "clicked", (GCallback)clickedme, label); gtk_widget_show_all(GTK_WIDGET(win)); gtk_main(); return 0; }
use iced::{ button, Button, Column, Element, Length, Text, Sandbox, Settings, Space, }; #[derive(Debug, Copy, Clone)] struct Pressed; struct Simple { value: i32, button: button::State, } impl Sandbox for Simple { type Message = Pressed; fn new() -> Simple { Simple { value: 0, button: button::State::new(), } } fn title(&self) -> String { "Simple Windowed Application".into() } fn view(&mut self) -> Element<Self::Message> { Column::new() .padding(20) .push({ let text = match self.value { 0 => "there have been no clicks yet".into(), 1 => "there has been 1 click".into(), n => format!("there have been {} clicks", n), }; Text::new(text).size(24) }).push( Space::with_height(Length::Fill) ).push( Button::new(&mut self.button, Text::new("Click Me!")) .on_press(Pressed) ).into() } fn update(&mut self, _: Self::Message) { self.value += 1; } } fn main() { let mut settings = Settings::default(); settings.window.size = (600, 400); Simple::run(settings).unwrap(); }
Singly-linked list_Element definition
struct link { struct link *next; int data; };
struct Node<T> { elem: T, next: Option<Box<Node<T>>>, }
Singly-linked list_Element insertion
void insert_append (struct link *anchor, struct link *newlink) { newlink->next = anchor->next; anchor->next = newlink; }
impl<T> List<T> { pub fn new() -> Self { List { head: None } } pub fn push(&mut self, elem: T) { let new_node = Box::new(Node { elem: elem, next: self.head.take(), }); self.head = Some(new_node); }
Singly-linked list_Traversal
struct link *first; struct link *iter; for(iter = first; iter != NULL; iter = iter->next) { }
pub struct IntoIter<T>(List<T>); impl<T> Iterator for IntoIter<T> { type Item = T; fn next(&mut self) -> Option<Self::Item> { self.0.head.take().map(|node| { let node = *node; self.0.head = node.next; node.elem }) } } pub struct Iter<'a, T: 'a> { next: Option<&'a Node<T>>, } impl<'a, T> Iterator for Iter<'a, T> { type Item = &'a T; fn next(&mut self) -> Option<Self::Item> { self.next.take().map(|node| { self.next = node.next.as_ref().map(|node| &**node); &node.elem }) } } pub struct IterMut<'a, T: 'a> { next: Option<&'a mut Node<T>>, } impl<'a, T> Iterator for IterMut<'a, T> { type Item = &'a mut T; fn next(&mut self) -> Option<Self::Item> { self.next.take().map(|node| { self.next = node.next.as_mut().map(|node| &mut **node); &mut node.elem }) } } impl<T> List<T> { pub fn into_iter(self) -> IntoIter<T> { IntoIter(self) } pub fn iter<'a>(&'a self) -> Iter<'a,T> { Iter { next: self.head.as_ref().map(|node| &**node) } } pub fn iter_mut(&mut self) -> IterMut<T> { IterMut { next: self.head.as_mut().map(|node| &mut **node) } } }
Sleep
#include <stdio.h> #include <unistd.h> int main() { unsigned int seconds; scanf("%u", &seconds); printf("Sleeping...\n"); sleep(seconds); printf("Awake!\n"); return 0; }
use std::{io, time, thread}; fn main() { println!("How long should we sleep in milliseconds?"); let mut sleep_string = String::new(); io::stdin().read_line(&mut sleep_string) .expect("Failed to read line"); let sleep_timer: u64 = sleep_string.trim() .parse() .expect("Not an integer"); let sleep_duration = time::Duration::from_millis(sleep_timer); println!("Sleeping..."); thread::sleep(sleep_duration); println!("Awake!"); }
Smith numbers
#include <stdlib.h> #include <stdio.h> #include <stdbool.h> int numPrimeFactors(unsigned x) { unsigned p = 2; int pf = 0; if (x == 1) return 1; else { while (true) { if (!(x % p)) { pf++; x /= p; if (x == 1) return pf; } else ++p; } } } void primeFactors(unsigned x, unsigned* arr) { unsigned p = 2; int pf = 0; if (x == 1) arr[pf] = 1; else { while (true) { if (!(x % p)) { arr[pf++] = p; x /= p; if (x == 1) return; } else p++; } } } unsigned sumDigits(unsigned x) { unsigned sum = 0, y; while (x) { y = x % 10; sum += y; x /= 10; } return sum; } unsigned sumFactors(unsigned* arr, int size) { unsigned sum = 0; for (int a = 0; a < size; a++) sum += sumDigits(arr[a]); return sum; } void listAllSmithNumbers(unsigned x) { unsigned *arr; for (unsigned a = 4; a < x; a++) { int numfactors = numPrimeFactors(a); arr = (unsigned*)malloc(numfactors * sizeof(unsigned)); if (numfactors < 2) continue; primeFactors(a, arr); if (sumDigits(a) == sumFactors(arr,numfactors)) printf("%4u ",a); free(arr); } } int main(int argc, char* argv[]) { printf("All the Smith Numbers < 10000 are:\n"); listAllSmithNumbers(10000); return 0; }
fn main () { let primes = vec![2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]; let mut solution = Vec::new(); let mut number; for i in 4..10000 { let mut prime_factors = Vec::new(); number = i; for j in &primes { while number % j == 0 { number = number / j; prime_factors.push(j); } if number == 1 { break; } } if number != 1 { prime_factors.push(&number); } if prime_factors.len() < 2 { continue; } if prime_factors.iter().fold(0, |n,x| n + x.to_string().chars().map(|d| d.to_digit(10).unwrap()).fold(0, |n,x| n + x)) == i.to_string().chars().map(|d| d.to_digit(10).unwrap()).fold(0, |n,x| n + x) { solution.push(i); } } println!("Smith numbers below 10000 ({}) : {:?}",solution.len(), solution); }
Sockets
#include <stdio.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netdb.h> const char *msg = "hello socket world"; int main() { int i, sock, len, slen; struct addrinfo hints, *addrs; memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; if (0 == getaddrinfo("localhost", "256", &hints, &addrs)) { sock = socket(addrs->ai_family, addrs->ai_socktype, addrs->ai_protocol); if ( sock >= 0 ) { if ( connect(sock, addrs->ai_addr, addrs->ai_addrlen) >= 0 ) { const char *pm = msg; do { len = strlen(pm); slen = send(sock, pm, len, 0); pm += slen; } while ((0 <= slen) && (slen < len)); } close(sock); } freeaddrinfo(addrs); } }
use std::io::prelude::*; use std::net::TcpStream; fn main() { let mut my_stream = TcpStream::connect("127.0.0.1:256").unwrap(); let _ = my_stream.write(b"hello socket world"); }
Soloway's recurring rainfall
#include <stdio.h> int main(int argc, char **argv) { (void)argc; (void)argv; float currentAverage = 0; unsigned int currentEntryNumber = 0; for (;;) { int ret, entry; printf("Enter rainfall int, 99999 to quit: "); ret = scanf("%d", &entry); if (ret) { if (entry == 99999) { printf("User requested quit.\n"); break; } else { currentEntryNumber++; currentAverage = currentAverage + (1.0f/currentEntryNumber)*entry - (1.0f/currentEntryNumber)*currentAverage; printf("New Average: %f\n", currentAverage); } } else { printf("Invalid input\n"); while (getchar() != '\n'); } } return 0; }
fn main() { let mut current_average:f32 = 0.0; let mut current_entry_number:u32 = 0; loop { let current_entry; println!("Enter rainfall int, 99999 to quit: "); let mut input_text = String::new(); std::io::stdin().read_line(&mut input_text).expect("Failed to read from stdin"); let trimmed = input_text.trim(); match trimmed.parse::<u32>() { Ok(new_entry) => current_entry = new_entry, Err(..) => { println!("Invalid input"); continue; } }; if current_entry == 99999 { println!("User requested quit."); break; } else { current_entry_number = current_entry_number + 1; current_average = current_average + (1.0 / current_entry_number as f32)*(current_entry as f32) - (1.0 / current_entry_number as f32)*current_average; println!("New Average: {}", current_average); } } }
Sort a list of object identifiers
#include <stdio.h> #include <stdlib.h> #include <string.h> typedef struct oid_tag { char* str_; int* numbers_; int length_; } oid; void oid_destroy(oid* p) { if (p != 0) { free(p->str_); free(p->numbers_); free(p); } } int char_count(const char* str, char ch) { int count = 0; for (const char* p = str; *p; ++p) { if (*p == ch) ++count; } return count; } oid* oid_create(const char* str) { oid* ptr = calloc(1, sizeof(oid)); if (ptr == 0) return 0; ptr->str_ = strdup(str); if (ptr->str_ == 0) { oid_destroy(ptr); return 0; } int dots = char_count(str, '.'); ptr->numbers_ = malloc(sizeof(int) * (dots + 1)); if (ptr->numbers_ == 0) { oid_destroy(ptr); return 0; } ptr->length_ = dots + 1; const char* p = str; for (int i = 0; i <= dots && *p;) { char* eptr = 0; int num = strtol(p, &eptr, 10); if (*eptr != 0 && *eptr != '.') { oid_destroy(ptr); return 0; } ptr->numbers_[i++] = num; p = eptr; if (*p) ++p; } return ptr; } int oid_compare(const void* p1, const void* p2) { const oid* o1 = *(oid* const*)p1; const oid* o2 = *(oid* const*)p2; int i1 = 0, i2 = 0; for (; i1 < o1->length_ && i2 < o2->length_; ++i1, ++i2) { if (o1->numbers_[i1] < o2->numbers_[i2]) return -1; if (o1->numbers_[i1] > o2->numbers_[i2]) return 1; } if (o1->length_ < o2->length_) return -1; if (o1->length_ > o2->length_) return 1; return 0; } int main() { const char* input[] = { "1.3.6.1.4.1.11.2.17.19.3.4.0.10", "1.3.6.1.4.1.11.2.17.5.2.0.79", "1.3.6.1.4.1.11.2.17.19.3.4.0.4", "1.3.6.1.4.1.11150.3.4.0.1", "1.3.6.1.4.1.11.2.17.19.3.4.0.1", "1.3.6.1.4.1.11150.3.4.0" }; const int len = sizeof(input)/sizeof(input[0]); oid* oids[len]; memset(oids, 0, sizeof(oids)); int i; for (i = 0; i < len; ++i) { oids[i] = oid_create(input[i]); if (oids[i] == 0) { fprintf(stderr, "Out of memory\n"); goto cleanup; } } qsort(oids, len, sizeof(oid*), oid_compare); for (i = 0; i < len; ++i) puts(oids[i]->str_); cleanup: for (i = 0; i < len; ++i) oid_destroy(oids[i]); return 0; }
fn split(s: &str) -> impl Iterator<Item = u64> + '_ { s.split('.').map(|x| x.parse().unwrap()) } fn main() { let mut oids = vec![ "1.3.6.1.4.1.11.2.17.19.3.4.0.10", "1.3.6.1.4.1.11.2.17.5.2.0.79", "1.3.6.1.4.1.11.2.17.19.3.4.0.4", "1.3.6.1.4.1.11150.3.4.0.1", "1.3.6.1.4.1.11.2.17.19.3.4.0.1", "1.3.6.1.4.1.11150.3.4.0", ]; oids.sort_by(|a, b| Iterator::cmp(split(a), split(b))); println!("{:#?}", oids); }
Sort an array of composite structures
#include <stdio.h> #include <stdlib.h> #include <ctype.h> typedef struct twoStringsStruct { char * key, *value; } sTwoStrings; int ord( char v ) { static char *dgts = "012345679"; char *cp; for (cp=dgts; v != *cp; cp++); return (cp-dgts); } int cmprStrgs(const sTwoStrings *s1,const sTwoStrings *s2) { char *p1 = s1->key; char *p2 = s2->key; char *mrk1, *mrk2; while ((tolower(*p1) == tolower(*p2)) && *p1) { p1++; p2++;} if (isdigit(*p1) && isdigit(*p2)) { long v1, v2; if ((*p1 == '0') ||(*p2 == '0')) { while (p1 > s1->key) { p1--; p2--; if (*p1 != '0') break; } if (!isdigit(*p1)) { p1++; p2++; } } mrk1 = p1; mrk2 = p2; v1 = 0; while(isdigit(*p1)) { v1 = 10*v1+ord(*p1); p1++; } v2 = 0; while(isdigit(*p2)) { v2 = 10*v2+ord(*p2); p2++; } if (v1 == v2) return(p2-mrk2)-(p1-mrk1); return v1 - v2; } if (tolower(*p1) != tolower(*p2)) return (tolower(*p1) - tolower(*p2)); for(p1=s1->key, p2=s2->key; (*p1 == *p2) && *p1; p1++, p2++); return (*p1 -*p2); } int maxstrlen( char *a, char *b) { int la = strlen(a); int lb = strlen(b); return (la>lb)? la : lb; } int main() { sTwoStrings toBsorted[] = { { "Beta11a", "many" }, { "alpha1", "This" }, { "Betamax", "sorted." }, { "beta3", "order" }, { "beta11a", "strings" }, { "beta001", "is" }, { "beta11", "which" }, { "beta041", "be" }, { "beta05", "in" }, { "beta1", "the" }, { "beta40", "should" }, }; #define ASIZE (sizeof(toBsorted)/sizeof(sTwoStrings)) int k, maxlens[ASIZE]; char format[12]; sTwoStrings *cp; qsort( (void*)toBsorted, ASIZE, sizeof(sTwoStrings),cmprStrgs); for (k=0,cp=toBsorted; k < ASIZE; k++,cp++) { maxlens[k] = maxstrlen(cp->key, cp->value); sprintf(format," %%-%ds", maxlens[k]); printf(format, toBsorted[k].value); } printf("\n"); for (k=0; k < ASIZE; k++) { sprintf(format," %%-%ds", maxlens[k]); printf(format, toBsorted[k].key); } printf("\n"); return 0; }
use std::cmp::Ordering; #[derive(Debug)] struct Employee { name: String, category: String, } impl Employee { fn new(name: &str, category: &str) -> Self { Employee { name: name.into(), category: category.into(), } } } impl PartialEq for Employee { fn eq(&self, other: &Self) -> bool { self.name == other.name } } impl Eq for Employee {} impl PartialOrd for Employee { fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(self.cmp(other)) } } impl Ord for Employee { fn cmp(&self, other: &Self) -> Ordering { self.name.cmp(&other.name) } } fn main() { let mut employees = vec![ Employee::new("David", "Manager"), Employee::new("Alice", "Sales"), Employee::new("Joanna", "Director"), Employee::new("Henry", "Admin"), Employee::new("Tim", "Sales"), Employee::new("Juan", "Admin"), ]; employees.sort(); for e in employees { println!("{:<6} : {}", e.name, e.category); } }
Sort an integer array
#include <stdlib.h> #include <stdio.h> int intcmp(const void *aa, const void *bb) { const int *a = aa, *b = bb; return (*a < *b) ? -1 : (*a > *b); } int main() { int nums[5] = {2,4,3,1,2}; qsort(nums, 5, sizeof(int), intcmp); printf("result: %d %d %d %d %d\n", nums[0], nums[1], nums[2], nums[3], nums[4]); return 0; }
fn main() { let mut a = vec!(9, 8, 7, 6, 5, 4, 3, 2, 1, 0); a.sort(); println!("{:?}", a); }
Sort disjoint sublist
#include <stdio.h> void bubble_sort(int *idx, int n_idx, int *buf) { int i, j, tmp; #define for_ij for (i = 0; i < n_idx; i++) for (j = i + 1; j < n_idx; j++) #define sort(a, b) if (a < b) { tmp = a; a = b; b = tmp;} for_ij { sort(idx[j], idx[i]); } for_ij { sort(buf[idx[j]], buf[idx[i]]);} #undef for_ij #undef sort } int main() { int values[] = {7, 6, 5, 4, 3, 2, 1, 0}; int idx[] = {6, 1, 7}; int i; printf("before sort:\n"); for (i = 0; i < 8; i++) printf("%d ", values[i]); printf("\n\nafter sort:\n"); bubble_sort(idx, 3, values); for (i = 0; i < 8; i++) printf("%d ", values[i]); printf("\n"); return 0; }
use std::collections::BTreeSet; fn disjoint_sort(array: &mut [impl Ord], indices: &[usize]) { let mut sorted = indices.to_owned(); sorted.sort_unstable_by_key(|k| &array[*k]); indices .iter() .zip(sorted.iter()) .map(|(&a, &b)| if a > b { (b, a) } else { (a, b) }) .collect::<BTreeSet<_>>() .iter() .for_each(|(a, b)| array.swap(*a, *b)) } fn main() { let mut array = [7, 6, 5, 4, 3, 2, 1, 0]; let indices = [6, 1, 7]; disjoint_sort(&mut array, &indices); println!("{:?}", array); }
Sort numbers lexicographically
#include <math.h> #include <stdio.h> #include <stdlib.h> #include <string.h> int compareStrings(const void *a, const void *b) { const char **aa = (const char **)a; const char **bb = (const char **)b; return strcmp(*aa, *bb); } void lexOrder(int n, int *ints) { char **strs; int i, first = 1, last = n, k = n, len; if (n < 1) { first = n; last = 1; k = 2 - n; } strs = malloc(k * sizeof(char *)); for (i = first; i <= last; ++i) { if (i >= 1) len = (int)log10(i) + 2; else if (i == 0) len = 2; else len = (int)log10(-i) + 3; strs[i-first] = malloc(len); sprintf(strs[i-first], "%d", i); } qsort(strs, k, sizeof(char *), compareStrings); for (i = 0; i < k; ++i) { ints[i] = atoi(strs[i]); free(strs[i]); } free(strs); } int main() { int i, j, k, n, *ints; int numbers[5] = {0, 5, 13, 21, -22}; printf("In lexicographical order:\n\n"); for (i = 0; i < 5; ++i) { k = n = numbers[i]; if (k < 1) k = 2 - k; ints = malloc(k * sizeof(int)); lexOrder(n, ints); printf("%3d: [", n); for (j = 0; j < k; ++j) { printf("%d ", ints[j]); } printf("\b]\n"); free(ints); } return 0; }
fn lex_sorted_vector(num: i32) -> Vec<i32> { let (min, max) = if num >= 1 { (1, num) } else { (num, 1) }; let mut str: Vec<String> = (min..=max).map(|i| i.to_string()).collect(); str.sort(); str.iter().map(|s| s.parse::<i32>().unwrap()).collect() } fn main() { for n in &[0, 5, 13, 21, -22] { println!("{}: {:?}", n, lex_sorted_vector(*n)); } }
Sort three variables
#include<string.h> #include<stdlib.h> #include<stdio.h> #define MAX 3 int main() { char values[MAX][100],tempStr[100]; int i,j,isString=0; double val[MAX],temp; for(i=0;i<MAX;i++){ printf("Enter %d%s value : ",i+1,(i==0)?"st":((i==1)?"nd":"rd")); fgets(values[i],100,stdin); for(j=0;values[i][j]!=00;j++){ if(((values[i][j]<'0' || values[i][j]>'9') && (values[i][j]!='.' ||values[i][j]!='-'||values[i][j]!='+')) ||((values[i][j]=='.' ||values[i][j]=='-'||values[i][j]=='+')&&(values[i][j+1]<'0' || values[i][j+1]>'9'))) isString = 1; } } if(isString==0){ for(i=0;i<MAX;i++) val[i] = atof(values[i]); } for(i=0;i<MAX-1;i++){ for(j=i+1;j<MAX;j++){ if(isString==0 && val[i]>val[j]){ temp = val[j]; val[j] = val[i]; val[i] = temp; } else if(values[i][0]>values[j][0]){ strcpy(tempStr,values[j]); strcpy(values[j],values[i]); strcpy(values[i],tempStr); } } } for(i=0;i<MAX;i++) isString==1?printf("%c = %s",'X'+i,values[i]):printf("%c = %lf",'X'+i,val[i]); return 0; }
fn main() { let mut array = [5, 1, 3]; array.sort(); println!("Sorted: {:?}", array); array.sort_by(|a, b| b.cmp(a)); println!("Reverse sorted: {:?}", array); }
Sort using a custom comparator
#include <stdlib.h> #include <string.h> #include <strings.h> int mycmp(const void *s1, const void *s2) { const char *l = *(const char **)s1, *r = *(const char **)s2; size_t ll = strlen(l), lr = strlen(r); if (ll > lr) return -1; if (ll < lr) return 1; return strcasecmp(l, r); } int main() { const char *strings[] = { "Here", "are", "some", "sample", "strings", "to", "be", "sorted" }; qsort(strings, sizeof(strings)/sizeof(*strings), sizeof(*strings), mycmp); return 0; }
fn main() { let mut words = ["Here", "are", "some", "sample", "strings", "to", "be", "sorted"]; words.sort_by(|l, r| Ord::cmp(&r.len(), &l.len()).then(Ord::cmp(l, r))); println!("{:?}", words); }
Sorting algorithms_Bogosort
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> bool is_sorted(int *a, int n) { while ( --n >= 1 ) { if ( a[n] < a[n-1] ) return false; } return true; } void shuffle(int *a, int n) { int i, t, r; for(i=0; i < n; i++) { t = a[i]; r = rand() % n; a[i] = a[r]; a[r] = t; } } void bogosort(int *a, int n) { while ( !is_sorted(a, n) ) shuffle(a, n); } int main() { int numbers[] = { 1, 10, 9, 7, 3, 0 }; int i; bogosort(numbers, 6); for (i=0; i < 6; i++) printf("%d ", numbers[i]); printf("\n"); }
extern crate rand; use rand::Rng; fn bogosort_by<T,F>(order: F, coll: &mut [T]) where F: Fn(&T, &T) -> bool { let mut rng = rand::thread_rng(); while !is_sorted_by(&order, coll) { rng.shuffle(coll); } } #[inline] fn is_sorted_by<T,F>(order: F, coll: &[T]) -> bool where F: Fn(&T,&T) -> bool, { coll[..].iter().zip(&coll[1..]).all(|(x,y)| order(x,y)) } fn main() { let mut testlist = [1,55,88,24,990876,312,67,0,854,13,4,7]; bogosort_by(|x,y| x < y, &mut testlist); println!("{:?}", testlist); bogosort_by(|x,y| x > y, &mut testlist); println!("{:?}", testlist); }
Sorting algorithms_Bubble sort
#include <stdio.h> void bubble_sort (int *a, int n) { int i, t, j = n, s = 1; while (s) { s = 0; for (i = 1; i < j; i++) { if (a[i] < a[i - 1]) { t = a[i]; a[i] = a[i - 1]; a[i - 1] = t; s = 1; } } j--; } } int main () { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; int n = sizeof a / sizeof a[0]; int i; for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); bubble_sort(a, n); for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); return 0; }
fn bubble_sort<T: Ord>(values: &mut[T]) { let mut n = values.len(); let mut swapped = true; while swapped { swapped = false; for i in 1..n { if values[i - 1] > values[i] { values.swap(i - 1, i); swapped = true; } } n = n - 1; } } fn main() { let mut numbers = [8, 7, 1, 2, 9, 3, 4, 5, 0, 6]; println!("Before: {:?}", numbers); bubble_sort(&mut numbers); println!("After: {:?}", numbers); let mut strings = ["empty", "beach", "art", "car", "deal"]; println!("Before: {:?}", strings); bubble_sort(&mut strings); println!("After: {:?}", strings); }
Sorting algorithms_Cocktail sort
#include <stdio.h> void swap(int *x, int *y) { if(x == y) return; *x ^= *y; *y ^= *x; *x ^= *y; } void cocktailsort(int *a, size_t n) { while(1) { char flag; size_t start[2] = {1, n - 1}, end[2] = {n, 0}, inc[2] = {1, -1}; for(int it = 0; it < 2; ++it) { flag = 1; for(int i = start[it]; i != end[it]; i += inc[it]) if(a[i - 1] > a[i]) { swap(a + i - 1, a + i); flag = 0; } if(flag) return; } } } int main(void) { int a[] = { 5, -1, 101, -4, 0, 1, 8, 6, 2, 3 }; size_t n = sizeof(a)/sizeof(a[0]); cocktailsort(a, n); for (size_t i = 0; i < n; ++i) printf("%d ", a[i]); return 0; }
fn cocktail_sort<T: PartialOrd>(a: &mut [T]) { let len = a.len(); loop { let mut swapped = false; let mut i = 0; while i + 1 < len { if a[i] > a[i + 1] { a.swap(i, i + 1); swapped = true; } i += 1; } if swapped { swapped = false; i = len - 1; while i > 0 { if a[i - 1] > a[i] { a.swap(i - 1, i); swapped = true; } i -= 1; } } if !swapped { break; } } } fn main() { let mut v = vec![10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]; println!("before: {:?}", v); cocktail_sort(&mut v); println!("after: {:?}", v); }
Sorting algorithms_Comb sort
void Combsort11(double a[], int nElements) { int i, j, gap, swapped = 1; double temp; gap = nElements; while (gap > 1 || swapped == 1) { gap = gap * 10 / 13; if (gap == 9 || gap == 10) gap = 11; if (gap < 1) gap = 1; swapped = 0; for (i = 0, j = gap; j < nElements; i++, j++) { if (a[i] > a[j]) { temp = a[i]; a[i] = a[j]; a[j] = temp; swapped = 1; } } } }
fn comb_sort<T: PartialOrd>(a: &mut [T]) { let len = a.len(); let mut gap = len; let mut swapped = true; while gap > 1 || swapped { gap = (4 * gap) / 5; if gap < 1 { gap = 1; } let mut i = 0; swapped = false; while i + gap < len { if a[i] > a[i + gap] { a.swap(i, i + gap); swapped = true; } i += 1; } } } fn main() { let mut v = vec![10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]; println!("before: {:?}", v); comb_sort(&mut v); println!("after: {:?}", v); }
Sorting algorithms_Counting sort
#include <stdio.h> #include <stdlib.h> void counting_sort_mm(int *array, int n, int min, int max) { int i, j, z; int range = max - min + 1; int *count = malloc(range * sizeof(*array)); for(i = 0; i < range; i++) count[i] = 0; for(i = 0; i < n; i++) count[ array[i] - min ]++; for(i = min, z = 0; i <= max; i++) { for(j = 0; j < count[i - min]; j++) { array[z++] = i; } } free(count); } void min_max(int *array, int n, int *min, int *max) { int i; *min = *max = array[0]; for(i=1; i < n; i++) { if ( array[i] < *min ) { *min = array[i]; } else if ( array[i] > *max ) { *max = array[i]; } } }
fn counting_sort( mut data: Vec<usize>, min: usize, max: usize, ) -> Vec<usize> { let mut count: Vec<usize> = Vec::with_capacity(data.len()); count.resize(data.len(), 0); for num in &data { count[num - min] = count[num - min] + 1; } let mut z: usize = 0; for i in min..max+1 { while count[i - min] > 0 { data[z] = i; z += 1; count[i - min] = count[i - min] - 1; } } data } fn main() { let arr1 = vec![1, 0, 2, 9, 3, 8, 4, 7, 5, 6]; println!("{:?}", counting_sort(arr1, 0, 9)); let arr2 = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; println!("{:?}", counting_sort(arr2, 0, 9)); let arr3 = vec![10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]; println!("{:?}", counting_sort(arr3, 0, 10)); }
Sorting algorithms_Gnome sort
void gnome_sort(int *a, int n) { int i=1, j=2, t; # define swap(i, j) { t = a[i]; a[i] = a[j]; a[j] = t; } while(i < n) { if (a[i - 1] > a[i]) { swap(i - 1, i); if (--i) continue; } i = j++; } # undef swap }
fn gnome_sort<T: PartialOrd>(a: &mut [T]) { let len = a.len(); let mut i: usize = 1; let mut j: usize = 2; while i < len { if a[i - 1] <= a[i] { i = j; j += 1; } else { a.swap(i - 1, i); i -= 1; if i == 0 { i = j; j += 1; } } } } fn main() { let mut v = vec![10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]; println!("before: {:?}", v); gnome_sort(&mut v); println!("after: {:?}", v); }
Sorting algorithms_Heapsort
#include <stdio.h> int max (int *a, int n, int i, int j, int k) { int m = i; if (j < n && a[j] > a[m]) { m = j; } if (k < n && a[k] > a[m]) { m = k; } return m; } void downheap (int *a, int n, int i) { while (1) { int j = max(a, n, i, 2 * i + 1, 2 * i + 2); if (j == i) { break; } int t = a[i]; a[i] = a[j]; a[j] = t; i = j; } } void heapsort (int *a, int n) { int i; for (i = (n - 2) / 2; i >= 0; i--) { downheap(a, n, i); } for (i = 0; i < n; i++) { int t = a[n - i - 1]; a[n - i - 1] = a[0]; a[0] = t; downheap(a, n - i - 1, 0); } } int main () { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; int n = sizeof a / sizeof a[0]; int i; for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); heapsort(a, n); for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); return 0; }
fn main() { let mut v = [4, 6, 8, 1, 0, 3, 2, 2, 9, 5]; heap_sort(&mut v, |x, y| x < y); println!("{:?}", v); } fn heap_sort<T, F>(array: &mut [T], order: F) where F: Fn(&T, &T) -> bool, { let len = array.len(); for start in (0..len / 2).rev() { shift_down(array, &order, start, len - 1) } for end in (1..len).rev() { array.swap(0, end); shift_down(array, &order, 0, end - 1) } } fn shift_down<T, F>(array: &mut [T], order: &F, start: usize, end: usize) where F: Fn(&T, &T) -> bool, { let mut root = start; loop { let mut child = root * 2 + 1; if child > end { break; } if child + 1 <= end && order(&array[child], &array[child + 1]) { child += 1; } if order(&array[root], &array[child]) { array.swap(root, child); root = child } else { break; } } }
Sorting algorithms_Insertion sort
#include <stdio.h> void insertion_sort(int*, const size_t); void insertion_sort(int *a, const size_t n) { for(size_t i = 1; i < n; ++i) { int key = a[i]; size_t j = i; while( (j > 0) && (key < a[j - 1]) ) { a[j] = a[j - 1]; --j; } a[j] = key; } } int main (int argc, char** argv) { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; const size_t n = sizeof(a) / sizeof(a[0]) ; for (size_t i = 0; i < n; i++) printf("%d%s", a[i], (i == (n - 1))? "\n" : " "); insertion_sort(a, n); for (size_t i = 0; i < n; i++) printf("%d%s", a[i], (i == (n - 1))? "\n" : " "); return 0; }
fn insertion_sort<T: std::cmp::Ord>(arr: &mut [T]) { for i in 1..arr.len() { let mut j = i; while j > 0 && arr[j] < arr[j-1] { arr.swap(j, j-1); j = j-1; } } }
Sorting algorithms_Merge sort
#include <stdio.h> #include <stdlib.h> void merge (int *a, int n, int m) { int i, j, k; int *x = malloc(n * sizeof (int)); for (i = 0, j = m, k = 0; k < n; k++) { x[k] = j == n ? a[i++] : i == m ? a[j++] : a[j] < a[i] ? a[j++] : a[i++]; } for (i = 0; i < n; i++) { a[i] = x[i]; } free(x); } void merge_sort (int *a, int n) { if (n < 2) return; int m = n / 2; merge_sort(a, m); merge_sort(a + m, n - m); merge(a, n, m); } int main () { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; int n = sizeof a / sizeof a[0]; int i; for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); merge_sort(a, n); for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); return 0; }
pub fn merge_sort1<T: Copy + Ord>(v: &mut [T]) { sort(v, &mut Vec::new()); fn sort<T: Copy + Ord>(v: &mut [T], t: &mut Vec<T>) { match v.len() { 0 | 1 => (), n => { if t.is_empty() { t.reserve_exact(n); t.resize(n, v[0]); } let m = n / 2; sort(&mut v[..m], t); sort(&mut v[m..], t); if v[m - 1] <= v[m] { return; } copy(v, t); merge(&t[..m], &t[m..n], v); } } } #[inline(always)] fn merge<T: Copy + Ord>(a: &[T], b: &[T], c: &mut [T]) { let (mut i, mut j) = (0, 0); for k in 0..c.len() { if i < a.len() && (j >= b.len() || a[i] <= b[j]) { c[k] = a[i]; i += 1; } else { c[k] = b[j]; j += 1; } } } #[inline(always)] fn copy<T: Copy>(src: &[T], dst: &mut [T]) { for i in 0..src.len() { dst[i] = src[i]; } } #[inline(always)] fn insertion_sort<T: Ord>(v: &mut [T]) { for i in 1..v.len() { let mut j = i; while j > 0 && v[j] < v[j - 1] { v.swap(j, j - 1); j -= 1; } } } }
Sorting algorithms_Quicksort
#include <stdio.h> void quicksort(int *A, int len); int main (void) { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; int n = sizeof a / sizeof a[0]; int i; for (i = 0; i < n; i++) { printf("%d ", a[i]); } printf("\n"); quicksort(a, n); for (i = 0; i < n; i++) { printf("%d ", a[i]); } printf("\n"); return 0; } void quicksort(int *A, int len) { if (len < 2) return; int pivot = A[len / 2]; int i, j; for (i = 0, j = len - 1; ; i++, j--) { while (A[i] < pivot) i++; while (A[j] > pivot) j--; if (i >= j) break; int temp = A[i]; A[i] = A[j]; A[j] = temp; } quicksort(A, i); quicksort(A + i, len - i); }
fn main() { println!("Sort numbers in descending order"); let mut numbers = [4, 65, 2, -31, 0, 99, 2, 83, 782, 1]; println!("Before: {:?}", numbers); quick_sort(&mut numbers, &|x,y| x > y); println!("After: {:?}\n", numbers); println!("Sort strings alphabetically"); let mut strings = ["beach", "hotel", "airplane", "car", "house", "art"]; println!("Before: {:?}", strings); quick_sort(&mut strings, &|x,y| x < y); println!("After: {:?}\n", strings); println!("Sort strings by length"); println!("Before: {:?}", strings); quick_sort(&mut strings, &|x,y| x.len() < y.len()); println!("After: {:?}", strings); } fn quick_sort<T,F>(v: &mut [T], f: &F) where F: Fn(&T,&T) -> bool { let len = v.len(); if len >= 2 { let pivot_index = partition(v, f); quick_sort(&mut v[0..pivot_index], f); quick_sort(&mut v[pivot_index + 1..len], f); } } fn partition<T,F>(v: &mut [T], f: &F) -> usize where F: Fn(&T,&T) -> bool { let len = v.len(); let pivot_index = len / 2; let last_index = len - 1; v.swap(pivot_index, last_index); let mut store_index = 0; for i in 0..last_index { if f(&v[i], &v[last_index]) { v.swap(i, store_index); store_index += 1; } } v.swap(store_index, len - 1); store_index }
Sorting algorithms_Radix sort
#include <stdio.h> #include <limits.h> #include <stdlib.h> #include <time.h> #define ARR_LEN(ARR) (sizeof ARR / sizeof *ARR) #define RAND_RNG(M,N) (M + rand() / (RAND_MAX / (N - M + 1) + 1)); static void swap(unsigned *a, unsigned *b) { unsigned tmp = *a; *a = *b; *b = tmp; } static void rad_sort_u(unsigned *from, unsigned *to, unsigned bit) { if (!bit || to < from + 1) return; unsigned *ll = from, *rr = to - 1; for (;;) { while (ll < rr && !(*ll & bit)) ll++; while (ll < rr && (*rr & bit)) rr--; if (ll >= rr) break; swap(ll, rr); } if (!(bit & *ll) && ll < to) ll++; bit >>= 1; rad_sort_u(from, ll, bit); rad_sort_u(ll, to, bit); } static void radix_sort(int *a, const size_t len) { size_t i; unsigned *x = (unsigned*) a; for (i = 0; i < len; i++) x[i] ^= INT_MIN; rad_sort_u(x, x + len, INT_MIN); for (i = 0; i < len; i++) x[i] ^= INT_MIN; } int main(void) { srand(time(NULL)); int x[16]; for (size_t i = 0; i < ARR_LEN(x); i++) x[i] = RAND_RNG(-128,127) radix_sort(x, ARR_LEN(x)); for (size_t i = 0; i < ARR_LEN(x); i++) printf("%d%c", x[i], i + 1 < ARR_LEN(x) ? ' ' : '\n'); }
fn merge(in1: &[i32], in2: &[i32], out: &mut [i32]) { let (left, right) = out.split_at_mut(in1.len()); left.clone_from_slice(in1); right.clone_from_slice(in2); } fn radix_sort(data: &mut [i32]) { for bit in 0..31 { let (small, big): (Vec<_>, Vec<_>) = data.iter().partition(|&&x| (x >> bit) & 1 == 0); merge(&small, &big, data); } let (negative, positive): (Vec<_>, Vec<_>) = data.iter().partition(|&&x| x < 0); merge(&negative, &positive, data); } fn main() { let mut data = [170, 45, 75, -90, -802, 24, 2, 66, -17, 2]; println!("Before: {:?}", data); radix_sort(&mut data); println!("After: {:?}", data); }
Sorting algorithms_Selection sort
#include <stdio.h> void selection_sort (int *a, int n) { int i, j, m, t; for (i = 0; i < n; i++) { for (j = i, m = i; j < n; j++) { if (a[j] < a[m]) { m = j; } } t = a[i]; a[i] = a[m]; a[m] = t; } } int main () { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; int n = sizeof a / sizeof a[0]; int i; for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); selection_sort(a, n); for (i = 0; i < n; i++) printf("%d%s", a[i], i == n - 1 ? "\n" : " "); return 0; }
fn selection_sort(array: &mut [i32]) { let mut min; for i in 0..array.len() { min = i; for j in (i+1)..array.len() { if array[j] < array[min] { min = j; } } let tmp = array[i]; array[i] = array[min]; array[min] = tmp; } } fn main() { let mut array = [ 9, 4, 8, 3, -5, 2, 1, 6 ]; println!("The initial array is {:?}", array); selection_sort(&mut array); println!(" The sorted array is {:?}", array); }
Sorting algorithms_Sleep sort
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use std::thread; fn sleepsort<I: Iterator<Item=u32>>(nums: I) { let threads: Vec<_> = nums.map(|n| thread::spawn(move || { thread::sleep_ms(n); println!("{}", n); })).collect(); for t in threads { t.join(); } } fn main() { sleepsort(std::env::args().skip(1).map(|s| s.parse().unwrap())); }
Spiral matrix
#include <stdio.h> #include <stdlib.h> #define valid(i, j) 0 <= i && i < m && 0 <= j && j < n && !s[i][j] int main(int c, char **v) { int i, j, m = 0, n = 0; if (c >= 2) m = atoi(v[1]); if (c >= 3) n = atoi(v[2]); if (m <= 0) m = 5; if (n <= 0) n = m; int **s = calloc(1, sizeof(int *) * m + sizeof(int) * m * n); s[0] = (int*)(s + m); for (i = 1; i < m; i++) s[i] = s[i - 1] + n; int dx = 1, dy = 0, val = 0, t; for (i = j = 0; valid(i, j); i += dy, j += dx ) { for (; valid(i, j); j += dx, i += dy) s[i][j] = ++val; j -= dx; i -= dy; t = dy; dy = dx; dx = -t; } for (t = 2; val /= 10; t++); for(i = 0; i < m; i++) for(j = 0; j < n || !putchar('\n'); j++) printf("%*d", t, s[i][j]); return 0; }
const VECTORS: [(isize, isize); 4] = [(1, 0), (0, 1), (-1, 0), (0, -1)]; pub fn spiral_matrix(size: usize) -> Vec<Vec<u32>> { let mut matrix = vec![vec![0; size]; size]; let mut movement = VECTORS.iter().cycle(); let (mut x, mut y, mut n) = (-1, 0, 1..); for (move_x, move_y) in std::iter::once(size) .chain((1..size).rev().flat_map(|n| std::iter::repeat(n).take(2))) .flat_map(|steps| std::iter::repeat(movement.next().unwrap()).take(steps)) { x += move_x; y += move_y; matrix[y as usize][x as usize] = n.next().unwrap(); } matrix } fn main() { for i in spiral_matrix(4).iter() { for j in i.iter() { print!("{:>2} ", j); } println!(); } }
Split a character string based on change of character
#include <stdio.h> #include <stdlib.h> #include <string.h> char *split(char *str); int main(int argc,char **argv) { char input[13]="gHHH5YY++ printf("%s\n",split(input)); } char *split(char *str) { char last=*str,*result=malloc(3*strlen(str)),*counter=result; for (char *c=str;*c;c++) { if (*c!=last) { strcpy(counter,", "); counter+=2; last=*c; } *counter=*c; counter++; } *(counter--)='\0'; return realloc(result,strlen(result)); }
fn splitter(string: &str) -> String { let chars: Vec<_> = string.chars().collect(); let mut result = Vec::new(); let mut last_mismatch = 0; for i in 0..chars.len() { if chars.len() == 1 { return chars[0..1].iter().collect(); } if i > 0 && chars[i-1] != chars[i] { let temp_result: String = chars[last_mismatch..i].iter().collect(); result.push(temp_result); last_mismatch = i; } if i == chars.len() - 1 { let temp_result: String = chars[last_mismatch..chars.len()].iter().collect(); result.push(temp_result); } } result.join(", ") } fn main() { let test_string = "g"; println!("input string: {}", test_string); println!("output string: {}", splitter(test_string)); let test_string = ""; println!("input string: {}", test_string); println!("output string: {}", splitter(test_string)); let test_string = "gHHH5YY++ println!("input string: {}", test_string); println!("output string: {}", splitter(test_string)); }
Square but not cube
#include <stdio.h> #include <math.h> int main() { int n = 1, count = 0, sq, cr; for ( ; count < 30; ++n) { sq = n * n; cr = (int)cbrt((double)sq); if (cr * cr * cr != sq) { count++; printf("%d\n", sq); } else { printf("%d is square and cube\n", sq); } } return 0; }
fn main() { let mut s = 1; let mut c = 1; let mut cube = 1; let mut n = 0; while n < 30 { let square = s * s; while cube < square { c += 1; cube = c * c * c; } if cube == square { println!("{} is a square and a cube.", square); } else { println!("{}", square); n += 1; } s += 1; } }
Stack
#include <stdio.h> #include <stdlib.h> #define DECL_STACK_TYPE(type, name) \ typedef struct stk_##name##_t{type *buf; size_t alloc,len;}*stk_##name; \ stk_##name stk_##name##_create(size_t init_size) { \ stk_##name s; if (!init_size) init_size = 4; \ s = malloc(sizeof(struct stk_##name##_t)); \ if (!s) return 0; \ s->buf = malloc(sizeof(type) * init_size); \ if (!s->buf) { free(s); return 0; } \ s->len = 0, s->alloc = init_size; \ return s; } \ int stk_##name##_push(stk_##name s, type item) { \ type *tmp; \ if (s->len >= s->alloc) { \ tmp = realloc(s->buf, s->alloc*2*sizeof(type)); \ if (!tmp) return -1; s->buf = tmp; \ s->alloc *= 2; } \ s->buf[s->len++] = item; \ return s->len; } \ type stk_##name##_pop(stk_##name s) { \ type tmp; \ if (!s->len) abort(); \ tmp = s->buf[--s->len]; \ if (s->len * 2 <= s->alloc && s->alloc >= 8) { \ s->alloc /= 2; \ s->buf = realloc(s->buf, s->alloc * sizeof(type));} \ return tmp; } \ void stk_##name##_delete(stk_##name s) { \ free(s->buf); free(s); } #define stk_empty(s) (!(s)->len) #define stk_size(s) ((s)->len) DECL_STACK_TYPE(int, int) int main(void) { int i; stk_int stk = stk_int_create(0); printf("pushing: "); for (i = 'a'; i <= 'z'; i++) { printf(" %c", i); stk_int_push(stk, i); } printf("\nsize now: %d", stk_size(stk)); printf("\nstack is%s empty\n", stk_empty(stk) ? "" : " not"); printf("\npoppoing:"); while (stk_size(stk)) printf(" %c", stk_int_pop(stk)); printf("\nsize now: %d", stk_size(stk)); printf("\nstack is%s empty\n", stk_empty(stk) ? "" : " not"); stk_int_delete(stk); return 0; }
fn main() { let mut stack = Vec::new(); stack.push("Element1"); stack.push("Element2"); stack.push("Element3"); assert_eq!(Some(&"Element3"), stack.last()); assert_eq!(Some("Element3"), stack.pop()); assert_eq!(Some("Element2"), stack.pop()); assert_eq!(Some("Element1"), stack.pop()); assert_eq!(None, stack.pop()); }
Stair-climbing puzzle
void step_up(void) { while (!step()) { step_up(); } }
fn step_up() { while !step() { step_up(); } }
Statistics_Basic
#include <stdio.h> #include <stdlib.h> #include <math.h> #include <stdint.h> #define n_bins 10 double rand01() { return rand() / (RAND_MAX + 1.0); } double avg(int count, double *stddev, int *hist) { double x[count]; double m = 0, s = 0; for (int i = 0; i < n_bins; i++) hist[i] = 0; for (int i = 0; i < count; i++) { m += (x[i] = rand01()); hist[(int)(x[i] * n_bins)] ++; } m /= count; for (int i = 0; i < count; i++) s += x[i] * x[i]; *stddev = sqrt(s / count - m * m); return m; } void hist_plot(int *hist) { int max = 0, step = 1; double inc = 1.0 / n_bins; for (int i = 0; i < n_bins; i++) if (hist[i] > max) max = hist[i]; if (max >= 60) step = (max + 59) / 60; for (int i = 0; i < n_bins; i++) { printf("[%5.2g,%5.2g]%5d ", i * inc, (i + 1) * inc, hist[i]); for (int j = 0; j < hist[i]; j += step) printf("#"); printf("\n"); } } typedef struct { uint64_t size; double sum, x2; uint64_t hist[n_bins]; } moving_rec; void moving_avg(moving_rec *rec, double *data, int count) { double sum = 0, x2 = 0; for (int i = 0; i < count; i++) { sum += data[i]; x2 += data[i] * data[i]; rec->hist[(int)(data[i] * n_bins)]++; } rec->sum += sum; rec->x2 += x2; rec->size += count; } int main() { double m, stddev; int hist[n_bins], samples = 10; while (samples <= 10000) { m = avg(samples, &stddev, hist); printf("size %5d: %g %g\n", samples, m, stddev); samples *= 10; } printf("\nHistograph:\n"); hist_plot(hist); printf("\nMoving average:\n N Mean Sigma\n"); moving_rec rec = { 0, 0, 0, {0} }; double data[100]; for (int i = 0; i < 10000; i++) { for (int j = 0; j < 100; j++) data[j] = rand01(); moving_avg(&rec, data, 100); if ((i % 1000) == 999) { printf("%4lluk %f %f\n", rec.size/1000, rec.sum / rec.size, sqrt(rec.x2 * rec.size - rec.sum * rec.sum)/rec.size ); } } }
#![feature(iter_arith)] extern crate rand; use rand::distributions::{IndependentSample, Range}; pub fn mean(data: &[f32]) -> Option<f32> { if data.is_empty() { None } else { let sum: f32 = data.iter().sum(); Some(sum / data.len() as f32) } } pub fn variance(data: &[f32]) -> Option<f32> { if data.is_empty() { None } else { let mean = mean(data).unwrap(); let mut sum = 0f32; for &x in data { sum += (x - mean).powi(2); } Some(sum / data.len() as f32) } } pub fn standard_deviation(data: &[f32]) -> Option<f32> { if data.is_empty() { None } else { let variance = variance(data).unwrap(); Some(variance.sqrt()) } } fn print_histogram(width: u32, data: &[f32]) { let mut histogram = [0; 10]; let len = histogram.len() as f32; for &x in data { histogram[(x * len) as usize] += 1; } let max_frequency = *histogram.iter().max().unwrap() as f32; for (i, &frequency) in histogram.iter().enumerate() { let bar_width = frequency as f32 * width as f32 / max_frequency; print!("{:3.1}: ", i as f32 / len); for _ in 0..bar_width as usize { print!("*"); } println!(""); } } fn main() { let range = Range::new(0f32, 1f32); let mut rng = rand::thread_rng(); for &number_of_samples in [1000, 10_000, 1_000_000].iter() { let mut data = vec![]; for _ in 0..number_of_samples { let x = range.ind_sample(&mut rng); data.push(x); } println!(" Statistics for sample size {}", number_of_samples); println!("Mean: {:?}", mean(&data)); println!("Variance: {:?}", variance(&data)); println!("Standard deviation: {:?}", standard_deviation(&data)); print_histogram(40, &data); } }
String append
#include<stdio.h> #include<string.h> int main() { char str[24]="Good Morning"; char *cstr=" to all"; char *cstr2=" !!!"; int x=0; if(sizeof(str)>strlen(str)+strlen(cstr)+strlen(cstr2)) { strcat(str,cstr); x=strlen(str); sprintf(&str[x],"%s",cstr2); printf("%s\n",str); } return 0; }
use std::ops::Add; fn main(){ let hello = String::from("Hello world"); println!("{}", hello.add("!!!!")); }
String case
#include <ctype.h> #include <stdio.h> void str_toupper(char *s) { while(*s) { *s=toupper(*s); s++; } } void str_tolower(char *s) { while(*s) { *s=tolower(*s); s++; } } int main(int argc, char *argv[]) { char t[255]="alphaBETA"; str_toupper(t); printf("uppercase: %s\n", t); str_tolower(t); printf("lowercase: %s\n", t); return 0; }
fn main() { println!("{}", "jalapeño".to_uppercase()); println!("{}", "JALAPEÑO".to_lowercase()); }
String concatenation
#include <stdio.h> #include <stdlib.h> #include <string.h> char *sconcat(const char *s1, const char *s2) { char *s0 = malloc(strlen(s1)+strlen(s2)+1); strcpy(s0, s1); strcat(s0, s2); return s0; } int main() { const char *s = "hello"; char *s2; printf("%s literal\n", s); printf("%s%s\n", s, " literal"); s2 = sconcat(s, " literal"); puts(s2); free(s2); }
fn main() { let s = "hello".to_owned(); println!("{}", s); let s1 = s + " world"; println!("{}", s1); }
String interpolation (included)
#include <stdio.h> int main() { const char *extra = "little"; printf("Mary had a %s lamb.\n", extra); return 0; }
fn main() { println!("Mary had a {} lamb", "little"); println!("{1} had a {0} lamb", "little", "Mary"); println!("{name} had a {adj} lamb", adj="little", name="Mary"); }
String length
#include <string.h> int main(void) { const char *string = "Hello, world!"; size_t length = strlen(string); return 0; }
fn main() { let s = "文字化け"; println!("Character length: {}", s.chars().count()); }
String matching
#include <string.h> #include <stdio.h> int startsWith(const char* container, const char* target) { size_t clen = strlen(container), tlen = strlen(target); if (clen < tlen) return 0; return strncmp(container, target, tlen) == 0; } int endsWith(const char* container, const char* target) { size_t clen = strlen(container), tlen = strlen(target); if (clen < tlen) return 0; return strncmp(container + clen - tlen, target, tlen) == 0; } int doesContain(const char* container, const char* target) { return strstr(container, target) != 0; } int main(void) { printf("Starts with Test ( Hello,Hell ) : %d\n", startsWith("Hello","Hell")); printf("Ends with Test ( Code,ode ) : %d\n", endsWith("Code","ode")); printf("Contains Test ( Google,msn ) : %d\n", doesContain("Google","msn")); return 0; }
fn print_match(possible_match: Option<usize>) { match possible_match { Some(match_pos) => println!("Found match at pos {}", match_pos), None => println!("Did not find any matches") } } fn main() { let s1 = "abcd"; let s2 = "abab"; let s3 = "ab"; assert!(s1.starts_with(s3)); assert!(s1.contains(s3)); print_match(s1.find(s3)); print_match(s1.find(s2)); assert!(s2.ends_with(s3)); }
String prepend
#include<stdio.h> #include<string.h> #include<stdlib.h> int main() { char str[100]="my String"; char *cstr="Changed "; char *dup; sprintf(str,"%s%s",cstr,(dup=strdup(str))); free(dup); printf("%s\n",str); return 0; }
let mut s = "World".to_string(); s.insert_str(0, "Hello "); println!("{}", s);
Strip a set of characters from a string
#include <string.h> #include <stdio.h> #include <stdlib.h> char *strip_chars(const char *string, const char *chars) { char * newstr = malloc(strlen(string) + 1); int counter = 0; for ( ; *string; string++) { if (!strchr(chars, *string)) { newstr[ counter ] = *string; ++ counter; } } newstr[counter] = 0; return newstr; } int main(void) { char *new = strip_chars("She was a soul stripper. She took my heart!", "aei"); printf("%s\n", new); free(new); return 0; }
fn strip_characters(original : &str, to_strip : &str) -> String { let mut result = String::new(); for c in original.chars() { if !to_strip.contains(c) { result.push(c); } } result }
Strip comments from a string
#include<stdio.h> int main() { char ch, str[100]; int i; do{ printf("\nEnter the string :"); fgets(str,100,stdin); for(i=0;str[i]!=00;i++) { if(str[i]=='#'||str[i]==';') { str[i]=00; break; } } printf("\nThe modified string is : %s",str); printf("\nDo you want to repeat (y/n): "); scanf("%c",&ch); fflush(stdin); }while(ch=='y'||ch=='Y'); return 0; }
fn strip_comment<'a>(input: &'a str, markers: &[char]) -> &'a str { input .find(markers) .map(|idx| &input[..idx]) .unwrap_or(input) .trim() } fn main() { println!("{:?}", strip_comment("apples, pears # and bananas", &['#', ';'])); println!("{:?}", strip_comment("apples, pears ; and bananas", &['#', ';'])); println!("{:?}", strip_comment("apples, pears and bananas ", &['#', ';'])); }
Strip whitespace from a string_Top and tail
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> char *rtrim(const char *s) { while( isspace(*s) || !isprint(*s) ) ++s; return strdup(s); } char *ltrim(const char *s) { char *r = strdup(s); if (r != NULL) { char *fr = r + strlen(s) - 1; while( (isspace(*fr) || !isprint(*fr) || *fr == 0) && fr >= r) --fr; *++fr = 0; } return r; } char *trim(const char *s) { char *r = rtrim(s); char *f = ltrim(r); free(r); return f; } const char *a = " this is a string "; int main() { char *b = rtrim(a); char *c = ltrim(a); char *d = trim(a); printf("'%s'\n'%s'\n'%s'\n", b, c, d); free(b); free(c); free(d); return 0; }
fn main() { let spaces = " \t\n\x0B\x0C\r \u{A0} \u{2000}\u{3000}"; let string_with_spaces = spaces.to_owned() + "String without spaces" + spaces; assert_eq!(string_with_spaces.trim(), "String without spaces"); assert_eq!(string_with_spaces.trim_left(), "String without spaces".to_owned() + spaces); assert_eq!(string_with_spaces.trim_right(), spaces.to_owned() + "String without spaces"); }
Substring
#define _CRT_SECURE_NO_WARNINGS #include <stdio.h> #include <stdlib.h> #include <string.h> void putm(char* string, size_t m) { while(*string && m--) putchar(*string++); } int main(void) { char string[] = "Programs for other encodings (such as 8-bit ASCII, or EUC-JP)." int n = 3; int m = 4; char knownCharacter = '('; char knownSubstring[] = "encodings"; putm(string+n-1, m ); putchar('\n'); puts(string+n+1); putchar('\n'); putm(string, strlen(string)-1); putchar('\n'); putm(strchr(string, knownCharacter), m ); putchar('\n'); putm(strstr(string, knownSubstring), m ); putchar('\n'); return EXIT_SUCCESS; }
let s = "abc文字化けdef"; let n = 2; let m = 3; println!("{}", s.chars().skip(n).take(m).collect::<String>()); println!("{}", s.chars().skip(n).collect::<String>()); println!("{}", s.chars().rev().skip(1).collect::<String>()); let cpos = s.find('b').unwrap(); println!("{}", s[cpos..].chars().take(m).collect::<String>()); let spos = s.find("けd").unwrap(); println!("{}", s[spos..].chars().take(m).collect::<String>());
Subtractive generator
#include<stdio.h> #define MOD 1000000000 int state[55], si = 0, sj = 0; int subrand(); void subrand_seed(int p1) { int i, j, p2 = 1; state[0] = p1 % MOD; for (i = 1, j = 21; i < 55; i++, j += 21) { if (j >= 55) j -= 55; state[j] = p2; if ((p2 = p1 - p2) < 0) p2 += MOD; p1 = state[j]; } si = 0; sj = 24; for (i = 0; i < 165; i++) subrand(); } int subrand() { int x; if (si == sj) subrand_seed(0); if (!si--) si = 54; if (!sj--) sj = 54; if ((x = state[si] - state[sj]) < 0) x += MOD; return state[si] = x; } int main() { subrand_seed(292929); int i; for (i = 0; i < 10; i++) printf("%d\n", subrand()); return 0; }
struct SubtractiveGenerator { modulo: i32, offsets: (u32, u32), state: Vec<i32>, position: usize, } impl SubtractiveGenerator { fn new(modulo: i32, first_offset: u32, second_offset: u32) -> Self { let state_size: usize = first_offset.try_into().unwrap(); assert!(first_offset <= i32::MAX as u32); assert!(first_offset > second_offset); SubtractiveGenerator { modulo, offsets: (first_offset, second_offset), state: Vec::with_capacity(state_size), position: 0, } } } impl Iterator for SubtractiveGenerator { type Item = i32; fn next(&mut self) -> Option<<Self as Iterator>::Item> { let state_size = self.offsets.0 as usize; assert_eq!(self.state.len(), state_size); self.position = (self.position + 1) % self.offsets.0 as usize; let i1 = (self.position as i32 - self.offsets.0 as i32).rem_euclid(state_size as i32); let i2 = (self.position as i32 - self.offsets.1 as i32).rem_euclid(state_size as i32); let p1 = self.state[i1 as usize]; let p2 = self.state[i2 as usize]; self.state[self.position] = (p1 - p2).rem_euclid(self.modulo); Some(self.state[self.position]) } } fn get_seeded_xpat2_gen(seed: i32) -> SubtractiveGenerator { let mut gen = SubtractiveGenerator::new(1_000_000_000, 55, 24); let state_size = gen.offsets.0 as usize; let mut pre_state = Vec::with_capacity(state_size); pre_state.push(seed); pre_state.push(1); for i in 2..state_size { pre_state.push((pre_state[i - 2] - pre_state[i - 1]).rem_euclid(gen.modulo)); } for i in 0..state_size { gen.state.push(pre_state[(34 * (i + 1)) % 55]); } gen.position = 54; for _ in 0..165 { gen.next(); } gen } fn main() { let gen = get_seeded_xpat2_gen(292929); for n in gen.take(5) { println!("{}", n); } }
Sudoku
#include <stdio.h> void show(int *x) { int i, j; for (i = 0; i < 9; i++) { if (!(i % 3)) putchar('\n'); for (j = 0; j < 9; j++) printf(j % 3 ? "%2d" : "%3d", *x++); putchar('\n'); } } int trycell(int *x, int pos) { int row = pos / 9; int col = pos % 9; int i, j, used = 0; if (pos == 81) return 1; if (x[pos]) return trycell(x, pos + 1); for (i = 0; i < 9; i++) used |= 1 << (x[i * 9 + col] - 1); for (j = 0; j < 9; j++) used |= 1 << (x[row * 9 + j] - 1); row = row / 3 * 3; col = col / 3 * 3; for (i = row; i < row + 3; i++) for (j = col; j < col + 3; j++) used |= 1 << (x[i * 9 + j] - 1); for (x[pos] = 1; x[pos] <= 9; x[pos]++, used >>= 1) if (!(used & 1) && trycell(x, pos + 1)) return 1; x[pos] = 0; return 0; } void solve(const char *s) { int i, x[81]; for (i = 0; i < 81; i++) x[i] = s[i] >= '1' && s[i] <= '9' ? s[i] - '0' : 0; if (trycell(x, 0)) show(x); else puts("no solution"); } int main(void) { solve( "5x..7...." "6..195..." ".98....6." "8...6...3" "4..8.3..1" "7...2...6" ".6....28." "...419..5" "....8..79" ); return 0; }
type Sudoku = [u8; 81]; fn is_valid(val: u8, x: usize, y: usize, sudoku_ar: &mut Sudoku) -> bool { (0..9).all(|i| sudoku_ar[y * 9 + i] != val && sudoku_ar[i * 9 + x] != val) && { let (start_x, start_y) = ((x / 3) * 3, (y / 3) * 3); (start_y..start_y + 3).all(|i| (start_x..start_x + 3).all(|j| sudoku_ar[i * 9 + j] != val)) } } fn place_number(pos: usize, sudoku_ar: &mut Sudoku) -> bool { (pos..81).find(|&p| sudoku_ar[p] == 0).map_or(true, |pos| { let (x, y) = (pos % 9, pos / 9); for n in 1..10 { if is_valid(n, x, y, sudoku_ar) { sudoku_ar[pos] = n; if place_number(pos + 1, sudoku_ar) { return true; } sudoku_ar[pos] = 0; } } false }) } fn pretty_print(sudoku_ar: Sudoku) { let line_sep = "------+-------+------"; println!("{}", line_sep); for (i, e) in sudoku_ar.iter().enumerate() { print!("{} ", e); if (i + 1) % 3 == 0 && (i + 1) % 9 != 0 { print!("| "); } if (i + 1) % 9 == 0 { println!(" "); } if (i + 1) % 27 == 0 { println!("{}", line_sep); } } } fn solve(sudoku_ar: &mut Sudoku) -> bool { place_number(0, sudoku_ar) } fn main() { let mut sudoku_ar: Sudoku = [ 8, 5, 0, 0, 0, 2, 4, 0, 0, 7, 2, 0, 0, 0, 0, 0, 0, 9, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 7, 0, 0, 2, 3, 0, 5, 0, 0, 0, 9, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 7, 0, 0, 1, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 6, 0, 4, 0 ]; if solve(&mut sudoku_ar) { pretty_print(sudoku_ar); } else { println!("Unsolvable"); } }
Sum and product of an array
int arg[] = { 1,2,3,4,5 }; int arg_length = sizeof(arg)/sizeof(arg[0]); int *end = arg+arg_length; int sum = 0, prod = 1; int *p; for (p = arg; p!=end; ++p) { sum += *p; prod *= *p; }
fn main() { let arr = vec![1, 2, 3, 4, 5, 6, 7, 8, 9]; let sum = arr.iter().fold(0i32, |a, &b| a + b); let product = arr.iter().fold(1i32, |a, &b| a * b); println!("the sum is {} and the product is {}", sum, product); let sum = arr.iter().sum::<i32>(); let product = arr.iter().product::<i32>(); println!("the sum is {} and the product is {}", sum, product); }
Sum digits of an integer
#include <stdio.h> int SumDigits(unsigned long long n, const int base) { int sum = 0; for (; n; n /= base) sum += n % base; return sum; } int main() { printf("%d %d %d %d %d\n", SumDigits(1, 10), SumDigits(12345, 10), SumDigits(123045, 10), SumDigits(0xfe, 16), SumDigits(0xf0e, 16) ); return 0; }
struct DigitIter(usize, usize); impl Iterator for DigitIter { type Item = usize; fn next(&mut self) -> Option<Self::Item> { if self.0 == 0 { None } else { let ret = self.0 % self.1; self.0 /= self.1; Some(ret) } } } fn main() { println!("{}", DigitIter(1234,10).sum::<usize>()); }
Sum multiples of 3 and 5
#include <stdio.h> #include <stdlib.h> unsigned long long sum35(unsigned long long limit) { unsigned long long sum = 0; for (unsigned long long i = 0; i < limit; i++) if (!(i % 3) || !(i % 5)) sum += i; return sum; } int main(int argc, char **argv) { unsigned long long limit; if (argc == 2) limit = strtoull(argv[1], NULL, 10); else limit = 1000; printf("%lld\n", sum35(limit)); return 0; }
extern crate rug; use rug::Integer; use rug::ops::Pow; fn main() { for i in [3, 20, 100, 1_000].iter() { let ten = Integer::from(10); let mut limit = Integer::from(Integer::from(&ten.pow(*i as u32)) - 1); let mut aux_3_1 = &limit.mod_u(3u32); let mut aux_3_2 = Integer::from(&limit - aux_3_1); let mut aux_3_3 = Integer::from(&aux_3_2/3); let mut aux_3_4 = Integer::from(3 + aux_3_2); let mut aux_3_5 = Integer::from(&aux_3_3*&aux_3_4); let mut aux_3_6 = Integer::from(&aux_3_5/2); let mut aux_5_1 = &limit.mod_u(5u32); let mut aux_5_2 = Integer::from(&limit - aux_5_1); let mut aux_5_3 = Integer::from(&aux_5_2/5); let mut aux_5_4 = Integer::from(5 + aux_5_2); let mut aux_5_5 = Integer::from(&aux_5_3*&aux_5_4); let mut aux_5_6 = Integer::from(&aux_5_5/2); let mut aux_15_1 = &limit.mod_u(15u32); let mut aux_15_2 = Integer::from(&limit - aux_15_1); let mut aux_15_3 = Integer::from(&aux_15_2/15); let mut aux_15_4 = Integer::from(15 + aux_15_2); let mut aux_15_5 = Integer::from(&aux_15_3*&aux_15_4); let mut aux_15_6 = Integer::from(&aux_15_5/2); let mut result_aux_1 = Integer::from(&aux_3_6 + &aux_5_6); let mut result = Integer::from(&result_aux_1 - &aux_15_6); println!("Sum for 10^{} : {}",i,result); } }
Sum of a series
#include <stdio.h> double Invsqr(double n) { return 1 / (n*n); } int main (int argc, char *argv[]) { int i, start = 1, end = 1000; double sum = 0.0; for( i = start; i <= end; i++) sum += Invsqr((double)i); printf("%16.14f\n", sum); return 0; }
const LOWER: i32 = 1; const UPPER: i32 = 1000; const NUMBER_OF_TERMS: i32 = (UPPER + 1) - LOWER; fn main() { println!("{}", (NUMBER_OF_TERMS * (LOWER + UPPER)) / 2); println!("{}", (LOWER..UPPER + 1).fold(0, |sum, x| sum + x)); }
Sum of squares
#include <stdio.h> double squaredsum(double *l, int e) { int i; double sum = 0.0; for(i = 0 ; i < e ; i++) sum += l[i]*l[i]; return sum; } int main() { double list[6] = {3.0, 1.0, 4.0, 1.0, 5.0, 9.0}; printf("%lf\n", squaredsum(list, 6)); printf("%lf\n", squaredsum(list, 0)); printf("%lf\n", squaredsum(NULL, 0)); return 0; }
fn sq_sum(v: &[f64]) -> f64 { v.iter().fold(0., |sum, &num| sum + num*num) } fn main() { let v = vec![3.0, 1.0, 4.0, 1.0, 5.5, 9.7]; println!("{}", sq_sum(&v)); let u : Vec<f64> = vec![]; println!("{}", sq_sum(&u)); }
Symmetric difference
#include <stdio.h> #include <string.h> const char *A[] = { "John", "Serena", "Bob", "Mary", "Serena" }; const char *B[] = { "Jim", "Mary", "John", "Jim", "Bob" }; #define LEN(x) sizeof(x)/sizeof(x[0]) void uniq(const char *x[], int len) { int i, j; for (i = 0; i < len; i++) for (j = i + 1; j < len; j++) if (x[j] && x[i] && !strcmp(x[i], x[j])) x[j] = 0; } int in_set(const char *const x[], int len, const char *match) { int i; for (i = 0; i < len; i++) if (x[i] && !strcmp(x[i], match)) return 1; return 0; } void show_diff(const char *const x[], int lenx, const char *const y[], int leny) { int i; for (i = 0; i < lenx; i++) if (x[i] && !in_set(y, leny, x[i])) printf(" %s\n", x[i]); } void show_sym_diff(const char *const x[], int lenx, const char *const y[], int leny) { show_diff(x, lenx, y, leny); show_diff(y, leny, x, lenx); } int main() { uniq(A, LEN(A)); uniq(B, LEN(B)); printf("A \\ B:\n"); show_diff(A, LEN(A), B, LEN(B)); printf("\nB \\ A:\n"); show_diff(B, LEN(B), A, LEN(A)); printf("\nA ^ B:\n"); show_sym_diff(A, LEN(A), B, LEN(B)); return 0; }
use std::collections::HashSet; fn main() { let a: HashSet<_> = ["John", "Bob", "Mary", "Serena"] .iter() .collect(); let b = ["Jim", "Mary", "John", "Bob"] .iter() .collect(); let diff = a.symmetric_difference(&b); println!("{:?}", diff); }
Synchronous concurrency
#include <stdlib.h> #include <stdio.h> #include <libco.h> void fail(const char *message) { perror(message); exit(1); } cothread_t reader; cothread_t printer; struct { char *buf; size_t len; size_t cap; } line; size_t count; void reader_entry(void) { FILE *input; size_t newcap; int c, eof, eol; char *newbuf; input = fopen("input.txt", "r"); if (input == NULL) fail("fopen"); line.buf = malloc(line.cap = 4096); if (line.buf == NULL) fail("malloc"); line.len = 0; do { c = fgetc(input); if (ferror(input)) fail("fgetc"); eof = (c == EOF); if (eof) { eol = (line.len > 0); } else { if (line.len == line.cap) { newcap = line.cap * 2; newbuf = realloc(line.buf, newcap); if (newbuf == NULL) fail("realloc"); line.buf = newbuf; line.cap = newcap; } line.buf[line.len++] = c; eol = (c == '\n'); } if (eol) { co_switch(printer); line.len = 0; } } while (!eof); free(line.buf); line.buf = NULL; printf("Printed %zu lines.\n", count); co_switch(printer); } int main() { reader = co_create(4096, reader_entry); printer = co_active(); count = 0; for (;;) { co_switch(reader); if (line.buf == NULL) break; fwrite(line.buf, 1, line.len, stdout); count++; } co_delete(reader); return 0; }
use std::fs::File; use std::io::BufRead; use std::io::BufReader; use std::sync::mpsc::{channel, sync_channel}; use std::thread; fn main() { let (reader_send, writer_recv) = channel(); let (writer_send, reader_recv) = sync_channel(0); let reader_work = move || { let file = File::open("input.txt").expect("Failed to open input.txt"); let reader = BufReader::new(file); for line in reader.lines() { match line { Ok(msg) => reader_send .send(msg) .expect("Failed to send via the channel"), Err(e) => println!("{}", e), } } drop(reader_send); let count = reader_recv .recv() .expect("Failed to receive count from printer."); println!("{}", count); }; let writer_work = move || { let mut line_count = 0; loop { match writer_recv.recv() { Ok(msg) => { println!("{}", msg); line_count += 1; } Err(_) => break, } } writer_send .send(line_count) .expect("Failed to send line count from writer."); drop(writer_send); }; let reader_handle = thread::spawn(reader_work); thread::spawn(writer_work); reader_handle .join() .expect("Failed to join the reader thread."); }
System time
#include<time.h> #include<stdio.h> #include<stdlib.h> int main(){ time_t my_time = time(NULL); printf("%s", ctime(&my_time)); return 0; }
extern crate chrono; use chrono::prelude::*; fn main() { let utc: DateTime<Utc> = Utc::now(); println!("{}", utc.format("%d/%m/%Y %T")); }
Take notes on the command line
#include <stdio.h> #include <time.h> #define note_file "NOTES.TXT" int main(int argc, char**argv) { FILE *note = 0; time_t tm; int i; char *p; if (argc < 2) { if ((note = fopen(note_file, "r"))) while ((i = fgetc(note)) != EOF) putchar(i); } else if ((note = fopen(note_file, "a"))) { tm = time(0); p = ctime(&tm); while (*p) fputc(*p != '\n'?*p:'\t', note), p++; for (i = 1; i < argc; i++) fprintf(note, "%s%c", argv[i], 1 + i - argc ? ' ' : '\n'); } if (note) fclose(note); return 0; }
extern crate chrono; use std::fs::OpenOptions; use std::io::{self, BufReader, BufWriter}; use std::io::prelude::*; use std::env; const FILENAME: &str = "NOTES.TXT"; fn show_notes() -> Result<(), io::Error> { let file = OpenOptions::new() .read(true) .create(true) .write(true) .open(FILENAME)?; let mut buf_reader = BufReader::new(file); let mut contents = String::new(); buf_reader.read_to_string(&mut contents)?; println!("{}", contents); Ok(()) } fn add_to_notes(note: &str) -> Result<(), io::Error> { let file = OpenOptions::new() .append(true) .create(true) .open(FILENAME)?; let mut buf_writer = BufWriter::new(file); let date_and_time = chrono::Local::now(); writeln!(buf_writer, "{}", date_and_time)?; writeln!(buf_writer, "\t{}", note) } fn main() { let note = env::args().skip(1).collect::<Vec<_>>(); if note.is_empty() { show_notes().expect("failed to print NOTES.TXT"); } else { add_to_notes(&note.join(" ")).expect("failed to write to NOTES.TXT"); } }
Temperature conversion
#include <stdio.h> #include <stdlib.h> double kelvinToCelsius(double k){ return k - 273.15; } double kelvinToFahrenheit(double k){ return k * 1.8 - 459.67; } double kelvinToRankine(double k){ return k * 1.8; } void convertKelvin(double kelvin) { printf("K %.2f\n", kelvin); printf("C %.2f\n", kelvinToCelsius(kelvin)); printf("F %.2f\n", kelvinToFahrenheit(kelvin)); printf("R %.2f", kelvinToRankine(kelvin)); } int main(int argc, const char * argv[]) { if (argc > 1) { double kelvin = atof(argv[1]); convertKelvin(kelvin); } return 0; }
fn main() -> std::io::Result<()> { print!("Enter temperature in Kelvin to convert: "); let mut input = String::new(); std::io::stdin().read_line(&mut input)?; match input.trim().parse::<f32>() { Ok(kelvin) => { if kelvin < 0.0 { println!("Negative Kelvin values are not acceptable."); } else { println!("{} K", kelvin); println!("{} °C", kelvin - 273.15); println!("{} °F", kelvin * 1.8 - 459.67); println!("{} °R", kelvin * 1.8); } } _ => println!("Could not parse the input to a number."), } Ok(()) }
Terminal control_Clear the screen
void cls(void) { printf("\33[2J"); }
print!("\x1B[2J");
Terminal control_Coloured text
#include <stdio.h> void table(const char *title, const char *mode) { int f, b; printf("\n\033[1m%s\033[m\n bg\t fg\n", title); for (b = 40; b <= 107; b++) { if (b == 48) b = 100; printf("%3d\t\033[%s%dm", b, mode, b); for (f = 30; f <= 97; f++) { if (f == 38) f = 90; printf("\033[%dm%3d ", f, f); } puts("\033[m"); } } int main(void) { int fg, bg, blink, inverse; table("normal ( ESC[22m or ESC[m )", "22;"); table("bold ( ESC[1m )", "1;"); table("faint ( ESC[2m ), not well supported", "2;"); table("italic ( ESC[3m ), not well supported", "3;"); table("underline ( ESC[4m ), support varies", "4;"); table("blink ( ESC[5m )", "5;"); table("inverted ( ESC[7m )", "7;"); return 0; }
const ESC: &str = "\x1B["; const RESET: &str = "\x1B[0m"; fn main() { println!("Foreground¦Background--------------------------------------------------------------"); print!(" ¦"); for i in 40..48 { print!(" ESC[{}m ", i); } println!("\n----------¦------------------------------------------------------------------------"); for i in 30..38 { print!("{}ESC[{}m ¦{}{1}m", RESET, i, ESC); for j in 40..48 { print!("{}{}m Rosetta ", ESC, j); } println!("{}", RESET); print!("{}ESC[{};1m ¦{}{1};1m", RESET, i, ESC); for j in 40..48 { print!("{}{}m Rosetta ", ESC, j); } println!("{}", RESET); } }
Terminal control_Ringing the terminal bell
#include <stdio.h> int main() { printf("\a"); return 0; }
fn main() { print!("\x07"); }
Ternary logic
#include <stdio.h> typedef enum { TRITTRUE, TRITMAYBE, TRITFALSE } trit; trit tritNot[3] = {TRITFALSE , TRITMAYBE, TRITTRUE}; trit tritAnd[3][3] = { {TRITTRUE, TRITMAYBE, TRITFALSE}, {TRITMAYBE, TRITMAYBE, TRITFALSE}, {TRITFALSE, TRITFALSE, TRITFALSE} }; trit tritOr[3][3] = { {TRITTRUE, TRITTRUE, TRITTRUE}, {TRITTRUE, TRITMAYBE, TRITMAYBE}, {TRITTRUE, TRITMAYBE, TRITFALSE} }; trit tritThen[3][3] = { { TRITTRUE, TRITMAYBE, TRITFALSE}, { TRITTRUE, TRITMAYBE, TRITMAYBE}, { TRITTRUE, TRITTRUE, TRITTRUE } }; trit tritEquiv[3][3] = { { TRITTRUE, TRITMAYBE, TRITFALSE}, { TRITMAYBE, TRITMAYBE, TRITMAYBE}, { TRITFALSE, TRITMAYBE, TRITTRUE } }; const char* tritString[3] = {"T", "?", "F"}; void demo_binary_op(trit operator[3][3], const char* name) { trit operand1 = TRITTRUE; trit operand2 = TRITTRUE; printf("\n"); for( operand1 = TRITTRUE; operand1 <= TRITFALSE; ++operand1 ) { for( operand2 = TRITTRUE; operand2 <= TRITFALSE; ++operand2 ) { printf("%s %s %s: %s\n", tritString[operand1], name, tritString[operand2], tritString[operator[operand1][operand2]]); } } } int main() { trit op1 = TRITTRUE; trit op2 = TRITTRUE; for( op1 = TRITTRUE; op1 <= TRITFALSE; ++op1 ) { printf("Not %s: %s\n", tritString[op1], tritString[tritNot[op1]]); } demo_binary_op(tritAnd, "And"); demo_binary_op(tritOr, "Or"); demo_binary_op(tritThen, "Then"); demo_binary_op(tritEquiv, "Equiv"); return 0; }
use std::{ops, fmt}; #[derive(Copy, Clone, Debug)] enum Trit { True, Maybe, False, } impl ops::Not for Trit { type Output = Self; fn not(self) -> Self { match self { Trit::True => Trit::False, Trit::Maybe => Trit::Maybe, Trit::False => Trit::True, } } } impl ops::BitAnd for Trit { type Output = Self; fn bitand(self, other: Self) -> Self { match (self, other) { (Trit::True, Trit::True) => Trit::True, (Trit::False, _) | (_, Trit::False) => Trit::False, _ => Trit::Maybe, } } } impl ops::BitOr for Trit { type Output = Self; fn bitor(self, other: Self) -> Self { match (self, other) { (Trit::True, _) | (_, Trit::True) => Trit::True, (Trit::False, Trit::False) => Trit::False, _ => Trit::Maybe, } } } impl Trit { fn imp(self, other: Self) -> Self { match self { Trit::True => other, Trit::Maybe => { if let Trit::True = other { Trit::True } else { Trit::Maybe } } Trit::False => Trit::True, } } fn eqv(self, other: Self) -> Self { match self { Trit::True => other, Trit::Maybe => Trit::Maybe, Trit::False => !other, } } } impl fmt::Display for Trit { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!( f, "{}", match self { Trit::True => 'T', Trit::Maybe => 'M', Trit::False => 'F', } ) } } static TRITS: [Trit; 3] = [Trit::True, Trit::Maybe, Trit::False]; fn main() { println!("not"); println!("-------"); for &t in &TRITS { println!(" {} | {}", t, !t); } table("and", |a, b| a & b); table("or", |a, b| a | b); table("imp", |a, b| a.imp(b)); table("eqv", |a, b| a.eqv(b)); } fn table(title: &str, f: impl Fn(Trit, Trit) -> Trit) { println!(); println!("{:3} | T M F", title); println!("-------------"); for &t1 in &TRITS { print!(" {} | ", t1); for &t2 in &TRITS { print!("{} ", f(t1, t2)); } println!(); } }
Test a function
#include <assert.h> int IsPalindrome(char *Str); int main() { assert(IsPalindrome("racecar")); assert(IsPalindrome("alice")); }
pub fn is_palindrome(s: &str) -> bool { let half = s.len(); s.chars().take(half).eq(s.chars().rev().take(half)) } #[cfg(test)] mod tests { use super::is_palindrome; #[test] fn test_is_palindrome() { assert!(is_palindrome("abba")); } }
Text processing_Max licenses in use
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #define INOUT_LEN 4 #define TIME_LEN 20 #define MAX_MAXOUT 1000 char inout[INOUT_LEN]; char time[TIME_LEN]; uint jobnum; char maxtime[MAX_MAXOUT][TIME_LEN]; int main(int argc, char **argv) { FILE *in = NULL; int l_out = 0, maxout=-1, maxcount=0; if ( argc > 1 ) { in = fopen(argv[1], "r"); if ( in == NULL ) { fprintf(stderr, "cannot read %s\n", argv[1]); exit(1); } } else { in = stdin; } while( fscanf(in, "License %s @ %s for job %u\n", inout, time, &jobnum) != EOF ) { if ( strcmp(inout, "OUT") == 0 ) l_out++; else l_out--; if ( l_out > maxout ) { maxout = l_out; maxcount=0; maxtime[0][0] = '\0'; } if ( l_out == maxout ) { if ( maxcount < MAX_MAXOUT ) { strncpy(maxtime[maxcount], time, TIME_LEN); maxcount++; } else { fprintf(stderr, "increase MAX_MAXOUT (now it is %u)\n", MAX_MAXOUT); exit(1); } } } printf("Maximum simultaneous license use is %d at the following times:\n", maxout); for(l_out=0; l_out < maxcount; l_out++) { printf("%s\n", maxtime[l_out]); } if ( in != stdin ) fclose(in); exit(0); }
type Timestamp = String; fn compute_usage<R, S, E>(lines: R) -> Result<(u32, Vec<Timestamp>), E> where S: AsRef<str>, R: Iterator<Item = Result<S, E>>, { let mut timestamps = Vec::new(); let mut current = 0; let mut maximum = 0; for line in lines { let line = line?; let line = line.as_ref(); if line.starts_with("License IN") { current -= 1; } else if line.starts_with("License OUT") { current += 1; if maximum <= current { let date = line.split_whitespace().nth(3).unwrap().to_string(); if maximum < current { maximum = current; timestamps.clear(); } timestamps.push(date); } } } Ok((maximum, timestamps)) } fn main() -> std::io::Result<()> { use std::io::{BufRead, BufReader}; let file = std::fs::OpenOptions::new().read(true).open("mlijobs.txt")?; let (max, timestamps) = compute_usage(BufReader::new(file).lines())?; println!("Maximum licenses out: {}", max); println!("At time(s): {:?}", timestamps); Ok(()) }
The Twelve Days of Christmas
#include<stdio.h> int main() { int i,j; char days[12][10] = { "First", "Second", "Third", "Fourth", "Fifth", "Sixth", "Seventh", "Eighth", "Ninth", "Tenth", "Eleventh", "Twelfth" }; char gifts[12][33] = { "Twelve drummers drumming", "Eleven pipers piping", "Ten lords a-leaping", "Nine ladies dancing", "Eight maids a-milking", "Seven swans a-swimming", "Six geese a-laying", "Five golden rings", "Four calling birds", "Three french hens", "Two turtle doves", "And a partridge in a pear tree." }; for(i=0;i<12;i++) { printf("\n\nOn the %s day of Christmas\nMy true love gave to me:",days[i]); for(j=i;j>=0;j--) { (i==0)?printf("\nA partridge in a pear tree."):printf("\n%s%c",gifts[11-j],(j!=0)?',':' '); } } return 0; }
fn main() { let days = ["first", "second", "third", "fourth", "fifth", "sixth", "seventh", "eighth", "ninth", "tenth", "eleventh", "twelfth"]; let gifts = ["A Partridge in a Pear Tree", "Two Turtle Doves and", "Three French Hens", "Four Calling Birds", "Five Golden Rings", "Six Geese a Laying", "Seven Swans a Swimming", "Eight Maids a Milking", "Nine Ladies Dancing", "Ten Lords a Leaping", "Eleven Pipers Piping", "Twelve Drummers Drumming"]; for i in 0..12 { println!("On the {} day of Christmas,", days[i]); println!("My true love gave to me:"); for j in (0..i + 1).rev() { println!("{}", gifts[j]); } println!() } }
Thue-Morse
#include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char *argv[]){ char sequence[256+1] = "0"; char inverse[256+1] = "1"; char buffer[256+1]; int i; for(i = 0; i < 8; i++){ strcpy(buffer, sequence); strcat(sequence, inverse); strcat(inverse, buffer); } puts(sequence); return 0; }
const ITERATIONS: usize = 8; fn neg(sequence: &String) -> String { sequence.chars() .map(|ch| { (1 - ch.to_digit(2).unwrap()).to_string() }) .collect::<String>() } fn main() { let mut sequence: String = String::from("0"); for i in 0..ITERATIONS { println!("{}: {}", i + 1, sequence); sequence = format!("{}{}", sequence, neg(&sequence)); } }
Tic-tac-toe
#include <stdio.h> #include <stdlib.h> int b[3][3]; int check_winner() { int i; for (i = 0; i < 3; i++) { if (b[i][0] && b[i][1] == b[i][0] && b[i][2] == b[i][0]) return b[i][0]; if (b[0][i] && b[1][i] == b[0][i] && b[2][i] == b[0][i]) return b[0][i]; } if (!b[1][1]) return 0; if (b[1][1] == b[0][0] && b[2][2] == b[0][0]) return b[0][0]; if (b[1][1] == b[2][0] && b[0][2] == b[1][1]) return b[1][1]; return 0; } void showboard() { const char *t = "X O"; int i, j; for (i = 0; i < 3; i++, putchar('\n')) for (j = 0; j < 3; j++) printf("%c ", t[ b[i][j] + 1 ]); printf("-----\n"); } #define for_ij for (i = 0; i < 3; i++) for (j = 0; j < 3; j++) int best_i, best_j; int test_move(int val, int depth) { int i, j, score; int best = -1, changed = 0; if ((score = check_winner())) return (score == val) ? 1 : -1; for_ij { if (b[i][j]) continue; changed = b[i][j] = val; score = -test_move(-val, depth + 1); b[i][j] = 0; if (score <= best) continue; if (!depth) { best_i = i; best_j = j; } best = score; } return changed ? best : 0; } const char* game(int user) { int i, j, k, move, win = 0; for_ij b[i][j] = 0; printf("Board postions are numbered so:\n1 2 3\n4 5 6\n7 8 9\n"); printf("You have O, I have X.\n\n"); for (k = 0; k < 9; k++, user = !user) { while(user) { printf("your move: "); if (!scanf("%d", &move)) { scanf("%*s"); continue; } if (--move < 0 || move >= 9) continue; if (b[i = move / 3][j = move % 3]) continue; b[i][j] = 1; break; } if (!user) { if (!k) { best_i = rand() % 3; best_j = rand() % 3; } else test_move(-1, 0); b[best_i][best_j] = -1; printf("My move: %d\n", best_i * 3 + best_j + 1); } showboard(); if ((win = check_winner())) return win == 1 ? "You win.\n\n": "I win.\n\n"; } return "A draw.\n\n"; } int main() { int first = 0; while (1) printf("%s", game(first = !first)); return 0; }
use GameState::{ComputerWin, Draw, PlayerWin, Playing}; use rand::prelude::*; #[derive(PartialEq, Debug)] enum GameState { PlayerWin, ComputerWin, Draw, Playing, } type Board = [[char; 3]; 3]; fn main() { let mut rng = StdRng::from_entropy(); let mut board: Board = [['1', '2', '3'], ['4', '5', '6'], ['7', '8', '9']]; draw_board(board); loop { player_turn(&mut board); if check_win(board) != Playing { break; } computer_turn(&mut rng, &mut board); if check_win(board) != Playing { break; } draw_board(board); } draw_board(board); let announcement = match check_win(board) { PlayerWin => "The Player has won!", ComputerWin => "The Computer has won!", Draw => "Draw!", Playing => unreachable!(), }; println!("{}", announcement); } fn is_empty(cell: &char) -> bool { *cell != 'X' && *cell != 'O' } fn check_win(board: Board) -> GameState { for (i, row) in board.iter().enumerate() { if row[0] == row[1] && row[0] == row[2] { return which_win(row[0]); } else if board[0][i] == board[1][i] && board[0][i] == board[2][i] { return which_win(board[0][i]); } } if board[0][0] == board[1][1] && board[0][0] == board[2][2] { return which_win(board[0][0]); } else if board[0][2] == board[1][1] && board[0][2] == board[2][0] { return which_win(board[0][2]); } let is_draw = board.iter().flatten().any(is_empty); if is_draw { Playing } else { Draw } } fn which_win(s: char) -> GameState { match s { 'X' => PlayerWin, 'O' => ComputerWin, _ => unreachable!(), } } fn player_turn(board: &mut Board) { use std::io; println!("Player, enter your field of choice!: "); let mut ln = String::new(); io::stdin() .read_line(&mut ln) .expect("Failed to read stdin"); let choice = ln.trim().parse::<usize>().expect("Failed to parse input"); let row = (choice - 1) / 3; let col = (choice - 1) % 3; if board[row][col] == 'X' || board[row][col] == 'O' { println!("Someone already took this field!"); player_turn(board); } else { board[row][col] = 'X'; } } fn computer_turn<R: Rng>(rng: &mut R, board: &mut Board) { let possible_choices: Vec<_> = board .iter() .flatten() .enumerate() .filter(|&(_, c)| is_empty(c)) .map(|(i, _)| i) .collect(); let choice = possible_choices.choose(rng).unwrap(); println!("Computer chose: {}", choice); let row = choice / 3; let col = choice % 3; board[row][col] = 'O'; } fn draw_board(board: Board) { for row in &board { println!("{} {} {}", row[0], row[1], row[2]); } }