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>
using namespace std;

int main(){
	
	string str, str1;

	while(getline(cin, str)){
		for(int i=0; i<26; i++){
			for(int j=0; j<str.length(); j++){
				if(str[j] == ' ' || str[j] == '.') continue;
				if(str[j] == 'z') str[j] = 'a';
				else{
					str[j] = str[j] + 1;
				}
			}
			
			str1 = "";
			for(int j=0; j<str.length(); j++){
				if(str[j] != ' ') str1 += str[j];
				else{
					if(str1 == "the" || str1 == "this" || str1 == "that"){
						cout << str << endl;
						return 0;
					}
					else str1 = "";
				}
			}
		}
	}

	return 0;
	
}

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

int main(int argc, char *argv[]){
  char c[26];
  for (int i = 0; i < 26; i++) {
    c[i] = 'a' + i;
  }
  vector<string> vs;
  string s;
  string ans[] = {"this", "that", "the"};
  vector<string> tmp;
  while(cin >> s)vs.push_back(s);
  vs[vs.size() - 1].pop_back();
  for (int k = 0; k < 26; k++) {
    tmp = vs;
    for (int i = 0; i < vs.size(); i++) {
      for (int j = 0; j < vs[i].length(); j++) {
        tmp[i][j] = c[(vs[i][j] - 'a' + k) % 25];
      }
    }
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < tmp.size(); j++) {
        if(tmp[j] == ans[i]){k = 50, i = 10, j = 1000;}
      }
    }
  }
  for (int i = 0; i < tmp.size(); i++) {
    std::cout << tmp[i];
    if(i == tmp.size() - 1)std::cout << "." << std::endl;
    else std::cout << " ";
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<sstream>
#include<vector>
using namespace std;
#define REP(i, j) for(int i = 0; i < j; i++)
#define FOR(i, j, k) for(int i = j; i < k; i++)
const int N = 30;

bool isOK(vector<string> v){
    REP(i, v.size()) if(v[i] == "the" || v[i] == "this" || v[i] == "that") return true;
    return false;
}

int main(){
    string str;
    while(getline(cin, str)){
        str = str.substr(0, str.length());
        string tmp;
        stringstream ss(str);
        vector<string> v;
        while(ss >>tmp) v.push_back(tmp);
        REP(z, N){
            REP(i, v.size()) REP(j, v[i].length()) v[i][j] = ++v[i][j] <= 'z'? v[i][j] : 'a';
            if(isOK(v)){
                cout <<v[0];
                FOR(i, 1, v.size()) cout <<" " <<v[i];
                cout <<'.' <<endl;
                break;
            }
        }
    }
    return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<string>
using namespace std;
int main(){
	
	char s[1000];
	while(cin.getline(s,1000)){
		for(int i=0;s[i]!='\0';i++){
			if((s[i]-s[i+1]=='t'-'h')&&(((s[i+1]-s[i+2]=='h'-'i')&&(s[i+2]-s[i+3]=='i'-'s'))||(s[i+1]-s[i+2]=='h'-'e')||((s[i+1]-s[i+2]=='h'-'a')&&(s[i+2]-s[i+3]=='a'-'t')))){
				for(int j=0;s[j]!='\0';j++){
					if((s[j]!=' ')&&(s[j]!='.')&&(s[j]!='\n')){
						if((s[j]+'t'-s[i]-'a')%24<0){
							putchar('z'+1+(s[j]+'t'-s[i]-'a')%24);
						}else{
							putchar((s[j]+'t'-s[i]-'a')%24+'a');
						}
					}else{
						putchar(s[j]);
					}
				}cout<<endl;
				break;
			}
		}
	}
	return 0;
}

C++: #include <fstream>
#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
using namespace std;

char shift(char c, int n) {
  if (c >= 'a' && c <= 'z')
    return (c + n <= 'z') ? c + n : 'a' + (c + n - 'z' - 1);
  else
    return c;
}

bool is_abc(char a) {
  return a >= 'a' && a <= 'z';
}

bool exist(string str, string c) {
  int id = str.find(c, 0);
  while (id != string::npos) {
    if (id > 0 && is_abc(str[id-1])) {
      id++;
      id = str.find(c, id);
    } else if (id + c.length() < str.length() && is_abc(str[id + c.length()])) {
      id++;
      id = str.find(c, id);
    } else {
      return true;
    }
  }
  return false;
}

int main() {
  // ifstream cin("../test.txt");
  vector<string> _the(26);
  vector<string> _this(26);
  vector<string> _that(26);
  _the[0] = "the";
  _this[0] = "this";
  _that[0] = "that";
  for (int i = 1; i < 26; i++) {
    for (int j = 0; j < 3; j++) {
      _the[i] += shift(_the[0][j], i);
    }
    for (int j = 0; j < 4; j++) {
      _this[i] += shift(_this[0][j], i);
      _that[i] += shift(_that[0][j], i);
    }
  }

  string str, nstr;
  // 復号化
  while (getline(cin, str)) {
    if (str.length() == 0) break;
    nstr = "";
    for (int i = 1; i < 26; i++) {
      if ( exist(str, _the[i]) || exist(str, _this[i]) || exist(str, _that[i])) {
        int len = str.length();
        for (int j = 0; j < len; j++) {
          nstr += shift(str.at(j), 26 - i);
        }
        break;
      }
    }

    cout << nstr << endl;
  }
  // 暗号化
  // while (getline(cin, str)) {
  //   for (int i = 1; i < 26; i++) {
  //     nstr = "";
  //     int len = str.length();
  //     for (int j = 0; j < len; j++) {
  //       nstr += shift(str[j], i);
  //     }
  //     cout << nstr << endl;
  //   }
  // }
}

C++: #include<iostream>
#include<list>
#include<string>
#include<cctype>
using namespace std;

bool checkString(int* key, string s);
void rotateChar(string* s, int i);

int main()
{
    list<string> table;
    string s;

    while(cin>>s) table.push_back(s);
    
    int key;
    list<string>::iterator i;
    for(i=table.begin(); i!=table.end(); i++){
        // cout << *i << " ";
        if( i->size() == 3 || i->size() == 4 )
            if( checkString(&key, *i) ) break;
    }
    
    int flag = 0;
    for(i=table.begin(); i!=table.end(); i++){
        if(!flag){
            rotateChar( &(*i), key);
            cout << *i;
            flag = 1;
        }else{
            rotateChar( &(*i), key);
            cout << " " << *i ;
        }
    }
    cout << endl;
            
    return 0;
}

void rotateChar(string* s, int i) // iは何文字ずらしたいか
{

    for(int j=0; j<s->size(); j++){
        if(!isalpha(s->at(j))){continue;}
        char c = s->at(j) - 'a';
        s->at(j) = 'a' + (c+i)%26;
    }
}

bool checkString(int* key, string s)
{

    for(int i=0; i<26; i++){
        string tmp = s;
        rotateChar(&tmp, i);
        // cout << tmp << endl;
        if( tmp=="the" || tmp=="this" || tmp=="that" ){
            *key=i;
            return true;
        }
    }
    return false;
}