Go: package main

import (
	"bufio"
	"os"
	"strings"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func cipher(text string, direction int, int_shift int) string {
	shift, offset := rune(int_shift), rune(26)
	runes := []rune(text)
	for index, char := range runes {
		switch direction {
		case 1:
			if char >= 'a' && char <= 'z'-shift || char >= 'A' && char <= 'Z'-shift {
				char = char + shift
			} else if char > 'z'-shift && char <= 'z' || char > 'Z'-shift && char <= 'Z' {
				char = char + shift - offset
			}
		case -1:
			if char >= 'a'+shift && char <= 'z' || char >= 'A'+shift && char <= 'Z' {
				char = char - shift
			} else if char >= 'a' && char < 'a'+shift || char >= 'A' && char < 'A'+shift {
				char = char - shift + offset
			}
		}
		runes[index] = char
	}
	return string(runes)
}

func main() {
	for {
		infos := strings.Split(nextString(), " ")
		plain := make([]string, len(infos))
		if len(infos) == 0 {
			break
		}
		// println(infos)
		Decryption:
			for i := 0; i < 26; i++ {
				for j := range infos {
					plain[j] = cipher(infos[j], 1, i)
				}
				for j := range plain {
					if plain[j] == "this" || plain[j] == "that" || plain[j] == "the" {
						break Decryption
					}
				}
			}
			fmt.Println(strings.Join(plain, " "))
	}
}

C++: #include<iostream>
#include<string.h>
#include<stdio.h>

int main(){

	char s[100];
	while (gets(s)){
		
		int diff;
		int flag = false;
		//一番最初に｛the,that,this｝がある場合
		diff = s[0] - 't';
		if ((s[1] - diff) == 'h'){
			//printf("%c\n", s[j+1] - diff);
			if ((s[2] - diff) == 'e'){
				//printf("%c\n", s[j + 2] - diff);
				if (s[3] == ' '){
					flag = true;
				}
			}
			else if ((s[2] - diff) == 'a'){
				//printf("%c\n", s[j + 2] - diff);
				if ((s[3] - diff) == 't'){
					//printf("%c\n", s[j + 3] - diff);
					if (s[4] == ' '){
						flag = true;
					}
				}
			}
			else if ((s[2] - diff) == 'i'){
				//printf("%c\n", s[j + 2] - diff);
				if ((s[3] - diff) == 's'){
					//printf("%c\n", s[j + 3] - diff);
					if (s[4] == ' '){
						flag = true;
					}
				}
			}
		}

		if (!flag){
			//一番以降に｛the,that,this｝がある場合
			for (int j = 1; j < strlen(s); j++){
				if ((s[j]) == ' '){
					diff = s[j + 1] - 't';
					if ((s[j + 1] - diff) == 't'){
						//printf("diff:%d\n", diff);
						if ((s[j + 2] - diff) == 'h'){
							//printf("%c\n", s[j+1] - diff);
							if ((s[j + 3] - diff) == 'e'){
								//printf("%c\n", s[j + 2] - diff);
								if (s[j + 4] == ' '){
									break;
								}
							}
							else if ((s[j + 3] - diff) == 'a'){
								//printf("%c\n", s[j + 2] - diff);
								if ((s[j + 4] - diff) == 't'){
									//printf("%c\n", s[j + 3] - diff);
									if (s[j + 5] == ' '){
										break;
									}
								}
							}
							else if ((s[j + 3] - diff) == 'i'){
								//printf("%c\n", s[j + 2] - diff);
								if ((s[j + 4] - diff) == 's'){
									//printf("%c\n", s[j + 3] - diff);
									if (s[j + 5] == ' '){
										break;
									}
								}
							}

						}
					}
				}
			}
		}
		//printf("diff:%d\n",diff);
		for (int i = 0; i < strlen(s); i++){
			if (s[i] == ' ' || s[i] == '.')continue;
			s[i] -= diff;
		}

		printf("%s\n", s);
	}
	return 0;
}

C++: #include <iostream>
#include <string>

using namespace std;

int main(int argc, const char * argv[])
{
    int shift = 1, i=0;
    string in,out;
    getline(cin,in);
    out = in;
    do {
        for (i=0; i<in.length(); i++) {
            if (in[i]!=' '&&in[i]!='.') {
                out[i] = ((in[i] + shift) % ('z'+1)) + 'a';
            }
        }
        if (out.find("the")!=std::string::npos||out.find("that")!=std::string::npos||out.find("this")!=std::string::npos) {
            break;
        }
        else
            shift += 1;
    } while (shift<=25);
    
    cout<<out<<endl;
    return 0;
}

C++: #include <iostream>
#include <string>
#include <sstream>

using namespace std;

constexpr unsigned ALPH_NUM = 26;

string shift(const string& line, int n);
bool judge(string& word);

int main()
{
    string line;
    while(getline(cin, line)) {
        bool is_solved = false;
        for (auto i = 0; i < ALPH_NUM && !is_solved; i++) {
            string shifted = shift(line, i);

            stringstream ss(shifted);
            string word;
            while (ss >> word) {
                if (judge(word)) {
                    cout << shifted << endl;
                    is_solved = true;
                    break;
                }
            }
        }
    }

    return 0;
}

string shift(const string& line, int n)
{
    string shifted = line;

    for (auto i = 0; i < line.size(); i++) {
        if (line.at(i) >= 'a' && line.at(i) <= 'z') {
            shifted.at(i) = static_cast<char>('a' + (line.at(i) - 'a' + n) % ('z' - 'a' + 1));
        } else {
            shifted.at(i) = line.at(i);
        }
    }

    return shifted;
}

bool judge(string& word)
{
    if (word.at(word.size() - 1) == '.') {
        word.erase(word.end() - 1);
    }

    return ((word == "the" || word == "this" || word == "that")? true: false);
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<string>

using namespace std;

int main()
{
  char s[81];

  while(gets(s) != NULL){

    int len = strlen(s);
    
    if(strstr(s,"this") || strstr(s,"that") || strstr(s,"the")){
      cout << s << endl;
      continue;
    }
    
    for(int i = 0;i < 'z' - 'a';i++){
      for(int j = 0;j < len;j++){
	if(s[j] >= 'a' && s[j] <= 'z'){
	  if(s[j]+1 > 'z'){
	    s[j] = 'a';
	  }
	  else{
	    s[j]++; 
	  }
	}
      }
      if(strstr(s,"this") || strstr(s,"that") || strstr(s,"the")){
	cout << s << endl;
	break;
      }
    }
  }
}

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

int main(void)
{
	int i;
	int len;
	int f;
	int n;
	char str[128];
	
	while (fgets(str, 100, stdin) != NULL){
		f = 0;
		n = 0;
		while (n < 25){
			len = strlen(str);
			for (i = 0; i < len; i++){
				if (strncmp(&str[i], "the", 3) == 0){
					f = 1;
				}
				if (strncmp(&str[i], "this", 4) == 0){
					f = 1;
				}
				if (strncmp(&str[i], "that", 4) == 0){
					f = 1;
				}
			}
			if (f == 1){
				break;
			}
			for (i = 0; i < len; i++){
				if (str[i] >= 'a' && str[i] < 'z'){
					str[i]++;
				}
				if (str[i] == 'z'){
					str[i] = 'a';
				}
			}
			n++;
		}
		printf("%s", str);
	}
	return (0);
}