Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

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 scanner.Scan() {
		infos := strings.Split(scanner.Text(), " ")
		plain := make([]string, len(infos))
		// fmt.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<cstring>
#include<cstdio>
using namespace std;
int main(){
	int f = 0,i;
	for(;;){
		char word[100]={0};
		for(i=0;;i++){
			if(scanf("%c",&word[i]) == EOF){f = 1;word[i]=10; break;}
			if(word[i] == 10){break;}
		}
		for(int l=0;l<26;l++){
			for(i=0;i<(int)strlen(word);i++){
				if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'i' && word[i+3] == 's' && word[i+4] == ' '){break;}
				else if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'a' && word[i+3] == 't' && word[i+4] == ' '){break;}
				else if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'e' && word[i+3] == ' '){break;}
				else if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'i' && word[i+3] == 's' && word[i+4] == '\n'){break;}
				else if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'a' && word[i+3] == 't' && word[i+4] == '\n'){break;}
				else if(word[i] == 't' && word[i+1] == 'h' && word[i+2] == 'e' && word[i+3] == '\n'){break;}
			}
			if(i != (int)strlen(word)){cout<<word;break;}
			for(i=0;i<(int)strlen(word);i++){
				if(word[i]==122){word[i]=97;}
				else if(word[i]>=97 && word[i]<122){word[i]++;}
			}
		}
		if(f == 1){break;}
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

int main(){
    string s;
    while(getline(cin, s)){
        for(int i=0;i<26;++i){
            string ans;
            for(int j=0;j<s.size();++j){
                if(s[j] >= 'a' && s[j] <= 'z'){
                    char c = (s[j] - 'a' + i) % 26 + 'a';
                    ans.push_back(c);
                }else{
                    ans.push_back(s[j]);
                }
            }
            if(ans.find("the") != -1 || ans.find("this") != -1 || ans.find("that") != -1){
                cout << ans << endl;
                break;
            }
        }
    }

    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <deque>
#include <list>
#include <string>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <stdio.h>

using namespace std;

int pat[3][3];
int len[3];
int chr[3];
int zure;
int size;
bool atteru[3];
char text[100];

int main() {
	//cin >> text;
	gets(text);
	//int size = text.size();
	int pt = 0;
	while (text[pt] != EOF) {
		pt++;
		size++;
	}

	pat[0][0] = 't' - 'h';
	pat[0][1] = 'h' - 'e';
	pat[1][0] = 't' - 'h';
	pat[1][1] = 'h' - 'i';
	pat[1][2] = 'i' - 's';
	pat[2][0] = 't' - 'h';
	pat[2][1] = 'h' - 'a';
	pat[2][2] = 'a' - 't';
	chr[0] = 'e';
	chr[1] = 's';
	chr[2] = 't';
	len[0] = 3;
	len[1] = 4;
	len[2] = 4;

	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 3; j++) {
			if (pat[i][j] < 0) pat[i][j] += 26;
		}
	}

	zure = -1;

	int cnt = 0;
	atteru[0] = true;
	atteru[1] = true;
	atteru[2] = true;
	for (int i = 0; i < size-1 && zure == -1; i++) {
		if (text[i+1] == ' ' || cnt > 3) continue;
		if (text[i] == ' ') {
			cnt = 0;
			atteru[0] = true;
			atteru[1] = true;
			atteru[2] = true;
			//cout << "yarinaoshi!" << endl;
			continue;
		}
		int dist = text[i] - text[i+1];
		if (dist < 0) dist += 26;
		for (int j = 0; j <= 2; j++) {
			if (!atteru[j]) continue;
			if (cnt >= len[j]-1) continue;
			if (dist != pat[j][cnt]) {
				atteru[j] = false;
				//cout << j << " ha tigau!" << endl;
				continue;
			} else if (cnt == len[j]-2) {
				//cout << j << " ha atteta!" << endl;
				zure = text[i+1] - chr[j];
				if (zure < 0) zure += 26;
				//cout << "zure = " << zure << endl;
			}
		}
		cnt++;
	}

	for (int i = 0; i < size; i++) {
		if (text[i] == '.') break;
		if (text[i] == ' ') continue;
		text[i] = text[i] - zure;
		if (text[i] < 'a') text[i] += 26;
	}

	cout << text << endl;

	return 0;
}

/*@@@@@@@@@@@@@@@@@@@@@@@@@*/
/*@                       @*/
/*@ debug output erased ? @*/
/*@                       @*/
/*@@@@@@@@@@@@@@@@@@@@@@@@@*/

C++: #include <bits/stdc++.h>
using namespace std;

int main()
{
	string s;
	getline(cin, s);
	int n = s.size();
	for (int i = 0; i < 26; i++) {
		bool flag = false;
		for (int j = 0; j + 3 <= n; j++) {
			if (s.substr(j, 3) == "the" && (j == 0 || s[j - 1] < 'a' || s[j - 1] > 'z') && (j + 3 == n || s[j + 3] < 'a' || s[j + 3] > 'z')) {
				flag = true;
			}
		}
		for (int j = 0; j + 4 <= n; j++) {
			if (s.substr(j, 4) == "this" && (j == 0 || s[j - 1] < 'a' || s[j - 1] > 'z') && (j + 4 == n || s[j + 4] < 'a' || s[j + 4] > 'z')) {
				flag = true;
			}
		}
		for (int j = 0; j + 4 <= n; j++) {
			if (s.substr(j, 4) == "that" && (j == 0 || s[j - 1] < 'a' || s[j - 1] > 'z') && (j + 4 == n || s[j + 4] < 'a' || s[j + 4] > 'z')) {
				flag = true;
			}
		}
		if (flag) {
			cout << s << endl;
			break;
		}
		for (int j = 0; j < n; j++) {
			if (s[j] >= 'a' && s[j] <= 'z') {
				s[j] = s[j] == 'z' ? 'a' : s[j] + 1;
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main(){
  string str;
  
  
  while(1){
    getline(cin,str);
    if(cin.eof())break;
    while(1){
      if(str.find("this")!=-1|| str.find("that")!=-1|| str.find("the")!=-1){cout<< str <<endl;break;}
      for(int i=0;i<(int)str.size();i++){
	
	if(str[i]=='a')str[i]='z';
	
	else if('b'<=str[i]&&str[i]<='z')str[i]-=1;
      } 
    }
  }
}

C++: #include <iostream>
#include <string.h>
#include <cstdio>
using namespace std;
char str1[82];
char str2[82];
void trans(char *orj,char *dest)
{
    int k=0,len=strlen(orj);
    for(int x=0;x<len;x++)
    {
        if(orj[x]>='a'&&orj[x]<='z')k=orj[x]-'a';
        else if(orj[x]>='A'&&orj[x]<='Z')k=orj[x]-'A';
        k=(k+22)%26;
        if(orj[x]>='a'&&orj[x]<='z')dest[x]='a'+k;
        else if(orj[x]>='A'&&orj[x]<='Z')dest[x]='A'+k;
        else dest[x]=orj[x];
    }
}
int main()
{
    while(gets(str1))
    {
        memset(str2,'\0',sizeof(str2));
        trans(str1,str2);
        cout<<str2<<endl;
    }
    return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>
#include <string>
int caesar(char s[]);
bool search(char s[]);

int main(){
	char s[256];
	int i,j=0,n=10;
	scanf("%[^\n]",&s);
	while(!search(s)){
		for(i=0;s[i]!='.';i++){
			if(s[i]!=' ') s[i]++;
			if(s[i]>122) s[i]=97;
		}
	}
	printf("%s\n",s);
	return 0;
}

bool search(char s[]){
	char *is,*e,*at;
	char *tmp;
	is="this";e="the";at="that";
	tmp = strchr(s,is[0]);
	if(tmp==NULL) return false;
	while(tmp[0]!=NULL){
		if(!strncmp(tmp,is,4))	return true;
		if(!strncmp(tmp,e,4))	return true;
		if(!strncmp(tmp,at,3))	return true;
		tmp++;
	}
	return false;
}

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

int main(){
	char s[100];

	int count = 0;

	gets(s);

	int diff = s[0] - 't';

	for (int j = 0; j < strlen(s); j++){
		if (s[j] == '.' || s[j] == ' ')
			continue;
		s[j] -= diff;
	}

	printf("%s\n",s);

	return 0;
}