WeixiangYan/CodeTransOcean huggingface dataset:
Task: Tonelli-Shanks algorithm

C: #include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

uint64_t modpow(uint64_t a, uint64_t b, uint64_t n) {
    uint64_t x = 1, y = a;
    while (b > 0) {
        if (b % 2 == 1) {
            x = (x * y) % n; 
        }
        y = (y * y) % n; 
        b /= 2;
    }
    return x % n;
}

struct Solution {
    uint64_t root1, root2;
    bool exists;
};

struct Solution makeSolution(uint64_t root1, uint64_t root2, bool exists) {
    struct Solution sol;
    sol.root1 = root1;
    sol.root2 = root2;
    sol.exists = exists;
    return sol;
}

struct Solution ts(uint64_t n, uint64_t p) {
    uint64_t q = p - 1;
    uint64_t ss = 0;
    uint64_t z = 2;
    uint64_t c, r, t, m;

    if (modpow(n, (p - 1) / 2, p) != 1) {
        return makeSolution(0, 0, false);
    }

    while ((q & 1) == 0) {
        ss += 1;
        q >>= 1;
    }

    if (ss == 1) {
        uint64_t r1 = modpow(n, (p + 1) / 4, p);
        return makeSolution(r1, p - r1, true);
    }

    while (modpow(z, (p - 1) / 2, p) != p - 1) {
        z++;
    }

    c = modpow(z, q, p);
    r = modpow(n, (q + 1) / 2, p);
    t = modpow(n, q, p);
    m = ss;

    while (true) {
        uint64_t i = 0, zz = t;
        uint64_t b = c, e;
        if (t == 1) {
            return makeSolution(r, p - r, true);
        }
        while (zz != 1 && i < (m - 1)) {
            zz = zz * zz % p;
            i++;
        }
        e = m - i - 1;
        while (e > 0) {
            b = b * b % p;
            e--;
        }
        r = r * b % p;
        c = b * b % p;
        t = t * c % p;
        m = i;
    }
}

void test(uint64_t n, uint64_t p) {
    struct Solution sol = ts(n, p);
    printf("n = %llu\n", n);
    printf("p = %llu\n", p);
    if (sol.exists) {
        printf("root1 = %llu\n", sol.root1);
        printf("root2 = %llu\n", sol.root2);
    } else {
        printf("No solution exists\n");
    }
    printf("\n");
}

int main() {
    test(10, 13);
    test(56, 101);
    test(1030, 10009);
    test(1032, 10009);
    test(44402, 100049);

    return 0;
}
Task: Monads_Maybe monad

C: #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

typedef enum type
{
  INT,
  STRING
} Type;

typedef struct maybe
{
  int i;
  char *s;
  Type t;
  _Bool is_something;
} Maybe;

void print_Maybe(Maybe *m)
{
  if (m->t == INT)
    printf("Just %d : INT\n", m->i);

  else if (m->t == STRING)
    printf("Just \"%s\" : STRING\n", m->s);

  else
    printf("Nothing\n");

}

Maybe *return_maybe(void *data, Type t)
{
  Maybe *m = malloc(sizeof(Maybe));
  if (t == INT)
  {
    m->i = *(int *) data;
    m->s = NULL;
    m->t = INT;
    m->is_something = true;
  }

  else if (t == STRING)
  {
    m->i = 0;
    m->s = data;
    m->t = STRING;
    m->is_something = true;
  }

  else
  {
    m->i = 0;
    m->s = NULL;
    m->t = 0;
    m->is_something = false;
  }

  return m;
}

Maybe *bind_maybe(Maybe *m, Maybe *(*f)(void *))
{
  Maybe *n = malloc(sizeof(Maybe));
  
  if (f(&(m->i))->is_something)
  {
    n->i = f(&(m->i))->i;
    n->s = f(&(m->i))->s;
    n->t = f(&(m->i))->t;
    n->is_something = true;
  }

  else
  {
    n->i = 0;
    n->s = NULL;
    n->t = 0;
    n->is_something = false;
  }
  return n;
}

Maybe *f_1(void *v) 
{
  Maybe *m = malloc(sizeof(Maybe));
  m->i = (*(int *) v) * (*(int *) v);
  m->s = NULL;
  m->t = INT;
  m->is_something = true;
  return m;
}

Maybe *f_2(void *v) 
{
  Maybe *m = malloc(sizeof(Maybe));
  m->i = 0;
  m->s = malloc(*(int *) v * sizeof(char) + 1);
  for (int i = 0; i < *(int *) v; i++)
  {
    m->s[i] = 'x';
  }
  m->s[*(int *) v + 1] = '\0';
  m->t = STRING;
  m->is_something = true;
  return m;
}

int main()
{
  int i = 7;
  char *s = "lorem ipsum dolor sit amet";

  Maybe *m_1 = return_maybe(&i, INT);
  Maybe *m_2 = return_maybe(s, STRING);

  print_Maybe(m_1); 
  print_Maybe(m_2); 

  print_Maybe(bind_maybe(m_1, f_1)); 
  print_Maybe(bind_maybe(m_1, f_2)); 

  print_Maybe(bind_maybe(bind_maybe(m_1, f_1), f_2)); 
}
Task: Monads_List monad

C: #include <stdio.h>
#include <stdlib.h>

#define MONAD void*
#define INTBIND(f, g, x) (f((int*)g(x)))
#define RETURN(type,x) &((type)*)(x)

MONAD boundInt(int *x) {
    return (MONAD)(x);
}

MONAD boundInt2str(int *x) {
    char buf[100];
    char*str= malloc(1+sprintf(buf, "%d", *x));
    sprintf(str, "%d", *x);
    return (MONAD)(str);
}

void task(int y) {
    char *z= INTBIND(boundInt2str, boundInt, &y);
    printf("%s\n", z);
    free(z);
}

int main() {
    task(13);
}
Task: Vector

C: #include<stdio.h>
#include<math.h>

#define pi M_PI

typedef struct{
	double x,y;
}vector;

vector initVector(double r,double theta){
	vector c;
	
	c.x = r*cos(theta);
	c.y = r*sin(theta);
	
	return c;
}

vector addVector(vector a,vector b){
	vector c;
	
	c.x = a.x + b.x;
	c.y = a.y + b.y;
	
	return c;
}

vector subtractVector(vector a,vector b){
	vector c;
	
	c.x = a.x - b.x;
	c.y = a.y - b.y;
	
	return c;
}

vector multiplyVector(vector a,double b){
	vector c;
	
	c.x = b*a.x;
	c.y = b*a.y;
	
	return c;
}

vector divideVector(vector a,double b){
	vector c;
	
	c.x = a.x/b;
	c.y = a.y/b;
	
	return c;
}

void printVector(vector a){
	printf("%lf %c %c %lf %c",a.x,140,(a.y>=0)?'+':'-',(a.y>=0)?a.y:fabs(a.y),150);
}

int main()
{
	vector a = initVector(3,pi/6);
	vector b = initVector(5,2*pi/3);
	
	printf("\nVector a : ");
	printVector(a);
	
	printf("\n\nVector b : ");
	printVector(b);
	
	printf("\n\nSum of vectors a and b : ");
	printVector(addVector(a,b));
	
	printf("\n\nDifference of vectors a and b : ");
	printVector(subtractVector(a,b));
	
	printf("\n\nMultiplying vector a by 3 : ");
	printVector(multiplyVector(a,3));
	
	printf("\n\nDividing vector b by 2.5 : ");
	printVector(divideVector(b,2.5));
	
	return 0;
}
Task: Elliptic curve arithmetic

C: #include <stdio.h>
#include <math.h>

#define C 7
typedef struct { double x, y; } pt;

pt zero(void) { return (pt){ INFINITY, INFINITY }; }


int is_zero(pt p) { return p.x > 1e20 || p.x < -1e20; }

pt neg(pt p) { return (pt){ p.x, -p.y }; }

pt dbl(pt p) {
	if (is_zero(p)) return p;

	pt r;
	double L = (3 * p.x * p.x) / (2 * p.y);
	r.x = L * L - 2 * p.x;
	r.y = L * (p.x - r.x) - p.y;
	return r;
}

pt add(pt p, pt q) {
	if (p.x == q.x && p.y == q.y) return dbl(p);
	if (is_zero(p)) return q;
	if (is_zero(q)) return p;

	pt r;
	double L = (q.y - p.y) / (q.x - p.x);
	r.x = L * L - p.x - q.x;
	r.y = L * (p.x - r.x) - p.y;
	return r;
}

pt mul(pt p, int n) {
	int i;
	pt r = zero();

	for (i = 1; i <= n; i <<= 1) {
		if (i & n) r = add(r, p);
		p = dbl(p);
	}
	return r;
}

void show(const char *s, pt p) {
	printf("%s", s);
	printf(is_zero(p) ? "Zero\n" : "(%.3f, %.3f)\n", p.x, p.y);
}

pt from_y(double y) {
	pt r;
	r.x = pow(y * y - C, 1.0/3);
	r.y = y;
	return r;
}

int main(void) {
	pt a, b, c, d;

	a = from_y(1);
	b = from_y(2);

	show("a = ", a);
	show("b = ", b);
	show("c = a + b = ", c = add(a, b));
	show("d = -c = ", d = neg(c));
	show("c + d = ", add(c, d));
	show("a + b + d = ", add(a, add(b, d)));
	show("a * 12345 = ", mul(a, 12345));

	return 0;
}
Task: Wagstaff primes

C: #include <stdio.h>
#include <string.h>
#include <gmp.h>

int main() {
    const int limit = 29;
    int count = 0;
    char tmp[40];
    mpz_t p, w;
    mpz_init_set_ui(p, 1);
    mpz_init(w);
    while (count < limit) {
       mpz_nextprime(p, p);
       mpz_set_ui(w, 1);
       unsigned long ulp = mpz_get_ui(p);
       mpz_mul_2exp(w, w, ulp);
       mpz_add_ui(w, w, 1);
       mpz_tdiv_q_ui(w, w, 3);
       if (mpz_probab_prime_p(w, 15) > 0) {
          ++count;
          char *ws = mpz_get_str(NULL, 10, w);
          size_t le = strlen(ws);
          if (le < 34) {
              strcpy(tmp, ws);
          } else {
              strncpy(tmp, ws, 15);
              strcpy(tmp + 15, "...");
              strncpy(tmp + 18, ws + le - 15, 16);
          }
          printf("%5lu: %s", ulp, tmp);
          if (le >=34) printf( " (%ld digits)", le);
          printf("\n");
       }
    }
    return 0;
}
Task: Catmull–Clark subdivision surface

C: vertex face_point(face f)
{
	int i;
	vertex v;

	if (!f->avg) {
		f->avg = vertex_new();
		foreach(i, v, f->v)
			if (!i) f->avg->pos = v->pos;
			else    vadd(f->avg->pos, v->pos);

		vdiv(f->avg->pos, len(f->v));
	}
	return f->avg;
}

#define hole_edge(e) (len(e->f)==1)
vertex edge_point(edge e)
{
	int i;
	face f;

	if (!e->e_pt) {
		e->e_pt = vertex_new();
		e->avg = e->v[0]->pos;
		vadd(e->avg, e->v[1]->pos);
		e->e_pt->pos = e->avg;

		if (!hole_edge(e)) {
			foreach (i, f, e->f)
				vadd(e->e_pt->pos, face_point(f)->pos);
			vdiv(e->e_pt->pos, 4);
		} else
			vdiv(e->e_pt->pos, 2);

		vdiv(e->avg, 2);
	}

	return e->e_pt;
}

#define hole_vertex(v) (len((v)->f) != len((v)->e))
vertex updated_point(vertex v)
{
	int i, n = 0;
	edge e;
	face f;
	coord_t sum = {0, 0, 0};

	if (v->v_new) return v->v_new;

	v->v_new = vertex_new();
	if (hole_vertex(v)) {
		v->v_new->pos = v->pos;
		foreach(i, e, v->e) {
			if (!hole_edge(e)) continue;
			vadd(v->v_new->pos, edge_point(e)->pos);
			n++;
		}
		vdiv(v->v_new->pos, n + 1);
	} else {
		n = len(v->f);
		foreach(i, f, v->f)
			vadd(sum, face_point(f)->pos);
		foreach(i, e, v->e)
			vmadd(sum, edge_point(e)->pos, 2, sum);
		vdiv(sum, n);
		vmadd(sum, v->pos, n - 3, sum);
		vdiv(sum, n);
		v->v_new->pos = sum;
	}

	return v->v_new;
}

model catmull(model m)
{
	int i, j, a, b, c, d;
	face f;
	vertex v, x;

	model nm = model_new();
	foreach (i, f, m->f) {
		foreach(j, v, f->v) {
			_get_idx(a, updated_point(v));
			_get_idx(b, edge_point(elem(f->e, (j + 1) % len(f->e))));
			_get_idx(c, face_point(f));
			_get_idx(d, edge_point(elem(f->e, j)));
			model_add_face(nm, 4, a, b, c, d);
		}
	}
	return nm;
}
Task: Bitmap_PPM conversion through a pipe

C: 
void print_jpg(image img, int qual);
Task: 24 game





Java: import java.util.*;

public class Game24 {
    static Random r = new Random();

    public static void main(String[] args) {

        int[] digits = randomDigits();
        Scanner in = new Scanner(System.in);

        System.out.print("Make 24 using these digits: ");
        System.out.println(Arrays.toString(digits));
        System.out.print("> ");

        Stack<Float> s = new Stack<>();
        long total = 0;
        for (char c : in.nextLine().toCharArray()) {
            if ('0' <= c && c <= '9') {
                int d = c - '0';
                total += (1 << (d * 5));
                s.push((float) d);
            } else if ("+/-*".indexOf(c) != -1) {
                s.push(applyOperator(s.pop(), s.pop(), c));
            }
        }
        if (tallyDigits(digits) != total)
            System.out.print("Not the same digits. ");
        else if (Math.abs(24 - s.peek()) < 0.001F)
            System.out.println("Correct!");
        else
            System.out.print("Not correct.");
    }

    static float applyOperator(float a, float b, char c) {
        switch (c) {
            case '+':
                return a + b;
            case '-':
                return b - a;
            case '*':
                return a * b;
            case '/':
                return b / a;
            default:
                return Float.NaN;
        }
    }

    static long tallyDigits(int[] a) {
        long total = 0;
        for (int i = 0; i < 4; i++)
            total += (1 << (a[i] * 5));
        return total;
    }

    static int[] randomDigits() {        
        int[] result = new int[4];
        for (int i = 0; i < 4; i++)
            result[i] = r.nextInt(9) + 1;
        return result;
    }
}
Task: Enforced immutability





Java: final int immutableInt = 4;
int mutableInt = 4;
mutableInt = 6; 
immutableInt = 6;
Task: Hofstadter Q sequence





Java: import java.util.HashMap;
import java.util.Map;

public class HofQ {
	private static Map<Integer, Integer> q = new HashMap<Integer, Integer>(){{
		put(1, 1);
		put(2, 1);
	}};
	
	private static int[] nUses = new int[100001];
	
	public static int Q(int n){
		nUses[n]++;
		if(q.containsKey(n)){
			return q.get(n);
		}
		int ans = Q(n - Q(n - 1)) + Q(n - Q(n - 2));
		q.put(n, ans);
		return ans;
	}
	
	public static void main(String[] args){
		for(int i = 1; i <= 10; i++){
			System.out.println("Q(" + i + ") = " + Q(i));
		}
		int last = 6;
		int count = 0;
		for(int i = 11; i <= 100000; i++){
			int curr = Q(i);
			if(curr < last) count++;
			last = curr;
			if(i == 1000) System.out.println("Q(1000) = " + curr);
		}
		System.out.println("Q(i) is less than Q(i-1) for i <= 100000 " + count + " times");
		
		
		int maxUses = 0, maxN = 0;
		for(int i = 1; i<nUses.length;i++){
			if(nUses[i] > maxUses){
				maxUses = nUses[i];
				maxN = i;
			}
		}
		System.out.println("Q(" + maxN + ") was called the most with " + maxUses + " calls");
	}
}
Task: Count occurrences of a substring





Java: public class CountSubstring {
	public static int countSubstring(String subStr, String str){
		return (str.length() - str.replace(subStr, "").length()) / subStr.length();
	}
	
	public static void main(String[] args){
		System.out.println(countSubstring("th", "the three truths"));
		System.out.println(countSubstring("abab", "ababababab"));
		System.out.println(countSubstring("a*b", "abaabba*bbaba*bbab"));
	}
}
Task: User input_Graphical





Java: import javax.swing.*;

public class GetInputSwing {
    public static void main(String[] args) throws Exception {
        int number = Integer.parseInt(
                JOptionPane.showInputDialog ("Enter an Integer"));
        String string = JOptionPane.showInputDialog ("Enter a String");
    }
}
Task: Fractal tree





Java: import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;

public class FractalTree extends JFrame {

    public FractalTree() {
        super("Fractal Tree");
        setBounds(100, 100, 800, 600);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    private void drawTree(Graphics g, int x1, int y1, double angle, int depth) {
        if (depth == 0) return;
        int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 10.0);
        int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 10.0);
        g.drawLine(x1, y1, x2, y2);
        drawTree(g, x2, y2, angle - 20, depth - 1);
        drawTree(g, x2, y2, angle + 20, depth - 1);
    }

    @Override
    public void paint(Graphics g) {
        g.setColor(Color.BLACK);
        drawTree(g, 400, 500, -90, 9);
    }

    public static void main(String[] args) {
        new FractalTree().setVisible(true);
    }
}
Task: Rock-paper-scissors





Java: import java.util.Arrays;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Random;

public class RPS {
	public enum Item{
		ROCK, PAPER, SCISSORS, ;
		public List<Item> losesToList;
		public boolean losesTo(Item other) {
			return losesToList.contains(other);
		}
		static {
			SCISSORS.losesToList = Arrays.asList(ROCK);
			ROCK.losesToList = Arrays.asList(PAPER);
			PAPER.losesToList = Arrays.asList(SCISSORS);
			
                }
	}
	
	public final Map<Item, Integer> counts = new EnumMap<Item, Integer>(Item.class){{
		for(Item item:Item.values())
			put(item, 1);
	}};

	private int totalThrows = Item.values().length;

	public static void main(String[] args){
		RPS rps = new RPS();
		rps.run();
	}

	public void run() {
		Scanner in = new Scanner(System.in);
		System.out.print("Make your choice: ");
		while(in.hasNextLine()){
			Item aiChoice = getAIChoice();
			String input = in.nextLine();
			Item choice;
			try{
				choice = Item.valueOf(input.toUpperCase());
			}catch (IllegalArgumentException ex){
				System.out.println("Invalid choice");
				continue;
			}
			counts.put(choice, counts.get(choice) + 1);
			totalThrows++;
			System.out.println("Computer chose: " + aiChoice);
			if(aiChoice == choice){
				System.out.println("Tie!");
			}else if(aiChoice.losesTo(choice)){
				System.out.println("You chose...wisely. You win!");
			}else{
				System.out.println("You chose...poorly. You lose!");
			}
			System.out.print("Make your choice: ");
		}
	}

	private static final Random rng = new Random();
	private Item getAIChoice() {
		int rand = rng.nextInt(totalThrows);
		for(Map.Entry<Item, Integer> entry:counts.entrySet()){
			Item item = entry.getKey();
			int count = entry.getValue();
			if(rand < count){
				List<Item> losesTo = item.losesToList;
				return losesTo.get(rng.nextInt(losesTo.size()));
			}
			rand -= count;
		}
		return null;
	}
}
Task: Hickerson series of almost integers





Java: import java.math.*;

public class Hickerson {

    final static String LN2 = "0.693147180559945309417232121458";

    public static void main(String[] args) {
        for (int n = 1; n <= 17; n++)
            System.out.printf("%2s is almost integer: %s%n", n, almostInteger(n));
    }

    static boolean almostInteger(int n) {
        BigDecimal a = new BigDecimal(LN2);
        a = a.pow(n + 1).multiply(BigDecimal.valueOf(2));

        long f = n;
        while (--n > 1)
            f *= n;

        BigDecimal b = new BigDecimal(f);
        b = b.divide(a, MathContext.DECIMAL128);

        BigInteger c = b.movePointRight(1).toBigInteger().mod(BigInteger.TEN);

        return c.toString().matches("0|9");
    }
}
Task: Read a configuration file





Java: import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class ConfigReader {
    private static final Pattern             LINE_PATTERN = Pattern.compile( "([^ =]+)[ =]?(.*)" );
    private static final Map<String, Object> DEFAULTS     = new HashMap<String, Object>() {{
        put( "needspeeling", false );
        put( "seedsremoved", false );
    }};

    public static void main( final String[] args ) {
        System.out.println( parseFile( args[ 0 ] ) );
    }

    public static Map<String, Object> parseFile( final String fileName ) {
        final Map<String, Object> result = new HashMap<String, Object>( DEFAULTS );
         BufferedReader      reader = null;

        try {
            reader = new BufferedReader( new FileReader( fileName ) );
            for ( String line; null != ( line = reader.readLine() );  ) {
                parseLine( line, result );
            }
        } catch ( final IOException x ) {
            throw new RuntimeException( "Oops: " + x, x );
        } finally {
            if ( null != reader ) try {
                reader.close();
            } catch ( final IOException x2 ) {
                System.err.println( "Could not close " + fileName + " - " + x2 );
            }
        }

        return result;
    }

    private static void parseLine( final String line, final Map<String, Object> map ) {
        if ( "".equals( line.trim() ) || line.startsWith( "#" ) || line.startsWith( ";" ) )
            return;

        final Matcher matcher = LINE_PATTERN.matcher( line );

        if ( ! matcher.matches() ) {
            System.err.println( "Bad config line: " + line );
            return;
        }

        final String key   = matcher.group( 1 ).trim().toLowerCase();
        final String value = matcher.group( 2 ).trim();

        if ( "".equals( value ) ) {
            map.put( key, true );
        } else if ( -1 == value.indexOf( ',' ) ) {
            map.put( key, value );
        } else {
            final String[] values = value.split( "," );

            for ( int i = 0; i < values.length; i++ ) {
                values[ i ] = values[ i ].trim();
            }
            map.put( key, Arrays.asList( values ) );
        }
    }
}
Task: Abbreviations, easy





Java: import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class AbbreviationsEasy {
    private static final Scanner input = new Scanner(System.in);
    private static final String  COMMAND_TABLE
            =       "  Add ALTer  BAckup Bottom  CAppend Change SCHANGE  CInsert CLAst COMPress COpy\n" +
                    " COUnt COVerlay CURsor DELete CDelete Down DUPlicate Xedit EXPand EXTract Find\n" +
                    " NFind NFINDUp NFUp CFind FINdup FUp FOrward GET Help HEXType Input POWerinput\n" +
                    " Join SPlit SPLTJOIN  LOAD  Locate CLocate  LOWercase UPPercase  LPrefix MACRO\n" +
                    " MErge MODify MOve MSG Next Overlay PARSE PREServe PURge PUT PUTD  Query  QUIT\n" +
                    " READ  RECover REFRESH RENum REPeat  Replace CReplace  RESet  RESTore  RGTLEFT\n" +
                    " RIght LEft  SAVE  SET SHift SI  SORT  SOS  STAck STATus TOP TRAnsfer Type Up";

    public static void main(String[] args) {
        String[]             cmdTableArr = COMMAND_TABLE.split("\\s+");
        Map<String, Integer> cmd_table   = new HashMap<String, Integer>();

        for (String word : cmdTableArr) {  
            cmd_table.put(word, countCaps(word));
        }

        System.out.print("Please enter your command to verify: ");
        String   userInput  = input.nextLine();
        String[] user_input = userInput.split("\\s+");

        for (String s : user_input) {
            boolean match = false; 
            for (String cmd : cmd_table.keySet()) {
                if (s.length() >= cmd_table.get(cmd) && s.length() <= cmd.length()) {
                    String temp = cmd.toUpperCase();
                    if (temp.startsWith(s.toUpperCase())) {
                        System.out.print(temp + " ");
                        match = true;
                    }
                }
            }
            if (!match) { 
                System.out.print("*error* ");
            }
        }
    }

    private static int countCaps(String word) {
        int numCaps = 0;
        for (int i = 0; i < word.length(); i++) {
            if (Character.isUpperCase(word.charAt(i))) {
                numCaps++;
            }
        }
        return numCaps;
    }
}
Task: Sorting algorithms_Stooge sort





Java: import java.util.Arrays;

public class Stooge {
    public static void main(String[] args) {
        int[] nums = {1, 4, 5, 3, -6, 3, 7, 10, -2, -5};
        stoogeSort(nums);
        System.out.println(Arrays.toString(nums));
    }

    public static void stoogeSort(int[] L) {
        stoogeSort(L, 0, L.length - 1);
    }

    public static void stoogeSort(int[] L, int i, int j) {
        if (L[j] < L[i]) {
            int tmp = L[i];
            L[i] = L[j];
            L[j] = tmp;
        }
        if (j - i > 1) {
            int t = (j - i + 1) / 3;
            stoogeSort(L, i, j - t);
            stoogeSort(L, i + t, j);
            stoogeSort(L, i, j - t);
        }
    }
}
Task: Truncate a file





Java: import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

public class TruncFile {
	public static void main(String[] args) throws IOException{
		if(args.length < 2){
			System.out.println("Usage: java TruncFile fileName newSize");
			return;
		}
		
		FileChannel outChan = new FileOutputStream(args[0], true).getChannel();
		long newSize = Long.parseLong(args[1]);
		outChan.truncate(newSize);
		outChan.close();
	}
}
Task: Read a specific line from a file





Java: package linenbr7;

import java.io.*;

public class LineNbr7 {

    public static void main(String[] args) throws Exception {
        File f = new File(args[0]);
        if (!f.isFile() || !f.canRead())
            throw new IOException("can't read " + args[0]);

        BufferedReader br = new BufferedReader(new FileReader(f));
        try (LineNumberReader lnr = new LineNumberReader(br)) {
            String line = null;
            int lnum = 0;
            while ((line = lnr.readLine()) != null
                    && (lnum = lnr.getLineNumber()) < 7) {
            }

            switch (lnum) {
                case 0:
                    System.out.println("the file has zero length");
                    break;
                case 7:
                    boolean empty = "".equals(line);
                    System.out.println("line 7: " + (empty ? "empty" : line));
                    break;
                default:
                    System.out.println("the file has only " + lnum + " line(s)");
            }
        }
    }
}