Go: package main

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

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 reflect.DeepEqual(infos, []string{}) {
			break
		}
		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 <vector>
#include <algorithm>
#include <cstdio>
#include <string>

#define rep(x,to) for(int x=0;x<to;x++)
#define rep2(x,from,to) for(x=from;x<to;x++)

using namespace std;


int main(void){

string inl;
vector<string> svs;
string ww[3] ={"the","this","that"};
	while(getline(cin,inl)){
		rep(i,26){
			rep(j,inl.size()){
				if(inl[j] >= 'a' && inl[j] <= 'z') inl[j] += 1;
				if(inl[j] > 'z' ) inl[j] -= 26;
				
				}
			if(inl.find(ww[0]) != string::npos 
				|| inl.find(ww[1]) != string::npos
				|| inl.find(ww[2]) != string::npos )  cout << inl << endl;
	//		 cout << i << "::" << inl << endl;

		}
	}
	
	return 0;
}

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

void shift(char *str, int len, int n){
	char t[] = "abcdefghijklmnopqrstuvwxyz";
	char c;
	for(int i=0; i<len; ++i){
		c = *(str + i);
		if(c >= 'a' && c <= 'z'){
			str[i] = t[(c-'a'+n)%26];
		}
	}
}

int main(void){
	char input[81];
	char copy[81];
	char *token;
	int len = 0;
	int n = 0;

	while(fgets(input, 80, stdin) != NULL){
		n = -1;
		strcpy(copy, input);

		token = strtok(copy, " .\n");
		while(token != NULL && n == -1){
			len = strlen(token);
			if(len == 4){
				for(int i=0;i<26; ++i){
					shift(token, 4, 1);
					if(strcmp(token, "this")==0 ||
						strcmp(token, "that")==0){
						n = i + 1;
						break;
					}
				}
			}else if(len ==3){
				for(int i=0;i<26; ++i){
					shift(token, 3, 1);
					if(strcmp(token, "the")==0){
						n = i + 1;
						break;
					}
				}
			}
			token = strtok(copy, " .\n");
		}
		shift(input, strlen(input), n);
		puts(input);
	}
	return 0;
}

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

using namespace std;

int main()
{
  string stro, str;
  while(getline(cin, stro)){
    for(int i = 1; i < 26; i++){
      str = stro;
      for(int j = 0; j < stro.length(); j++){
	if(str[j] != ' ' && str[j] != '.' && str[j] != '\n')
	  if(str[j] + i > 'z')
	    str[j] += i - 26;
	  else
	    str[j] += i;
      }
      unsigned f_the = str.find("the", 0);
      unsigned f_this = str.find("this", 0);
      unsigned f_that = str.find("that", 0);
      if((f_the != string::npos && f_the == 0 && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\n')) || (f_this != string::npos && f_this == 0 && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\n')) || (f_that != string::npos && f_that == 0 && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\n')))
	cout << str << endl;
      else if((f_the != string::npos && (str[f_the - 1] == ' ' || str[f_the - 1] == '.' || str[f_the - 1] == '\n') && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\n')) || (f_this != string::npos && (str[f_this - 1] == ' ' || str[f_this - 1] == '.' || str[f_this - 1] == '\n') && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\n')) || (f_that != string::npos && (str[f_that - 1] == ' ' || str[f_that - 1] == '.' || str[f_that - 1] == '\n') && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\n')))
	cout << str << endl;	 
    }
  }
}

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

using namespace std;

int main()
{
  auto const rot = []( string s, int g )
    {
      for( char& c : s )
        if ( c >= 'a' && c <= 'z' )
          c = (c - 'a' + g) % 26 + 'a';
      return s;
    };

  string s;
  while( getline( cin, s ) ) {
    for( int g=0; g<26; ++g ) {
      auto const& t = rot( s, g );
      if ( t.find( "the" ) != string::npos
           || t.find( "this" ) != string::npos
           || t.find( "that" ) != string::npos
           ) {
        cout << t << endl;
        break;
      }
    }
  }
}

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

std::string Caesar(std::string str, int tranceNum )
{
	for(size_t i=0; i<str.length(); ++i)
	{
		if(str[i]!='.')
		{
			int chNum = 0;
	
			chNum = str[i];

			chNum += tranceNum;

			chNum = (chNum-97)%26+97;
	
			str[i] = chNum;	
		
		}
	}

	return str;
}

int main(void)
{
	std::string str;
	
	std::vector<std::string> sentence;

	while(1)
	{	
		while(std::cin >> str)
		{
			sentence.push_back(str);
				
			if(sentence[sentence.size()-1][sentence[sentence.size()-1].length()-1]=='.')
			{
				break;
			}
		}

		if(std::cin.eof())
		{
			break;
		}

		for(bool flg=1; flg; )
		{
			for(size_t j=0; j<sentence.size(); ++j)
			{
			sentence[j] = Caesar(sentence[j],1);	
			}
	
			for(size_t j=0; (j<sentence.size()) && flg; ++j)
			{
				switch(sentence[j].length())
				{
				case 3:
					flg = (sentence[j]=="the") ? 0 : 1;
					break;
				case 4:
					flg = (sentence[j]=="that" || sentence[j]=="this") ? 0 : 1;
					break;
				case 5:
					flg = (sentence[j]=="that." || sentence[j]=="this.") ? 0 : 1;
					break;
				default:
					break;
				}
			}
		}
		for(size_t j=0; j<sentence.size(); ++j)
		{
			std::cout << sentence[j] << ' ';
		}
		std::cout << '\n';
	
		sentence.clear();
		}
}

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

using namespace std;

int main() {

  string str;


  while(getline(cin,str)) {

    //ê¶¸Â¸ç·
    for(int i=0;i<26;i++) {

      for(int j=0;j<str.size();j++) {

	if(str[j]>='a' && str[j]<'z') str[j]+=1;

	else if(str[j]=='z') str[j]='a';

      }

      //the,this,thatª é©Ç¤©»è
      if(str.find("the")!=string::npos || str.find("this")!=string::npos || str.find("that")!=string::npos) {

	cout << str << endl;

      }

    }

  }

  return 0;

}

C++: #include <cstring>
#include <iostream>
#include <string>
using namespace std;
void caesar(string &s, int n) {
  int i;
  char c;
  for (i = 0; c = s[i]; i++) {
    if (c >= 'a' && c <= 'z') 
      s[i] = 'a' + (c - 'a' + n) % 26;
  }
}
int main() {
  int n;
  string s;
  while (getline(cin, s)) {
    for (n = 0; n < 26; n++) {
      caesar(s, 1);
      if (s.find("the") != string::npos || s.find("this") != string::npos || s.find("that") != string::npos) {
        cout << s << endl;
        break;
      }
    }
  }
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

void f(string &s)
{
    for (char &c : s) {
        if ('a' <= c && c <= 'z') c = (c - 'a' + 25) % 26 + 'a';
    }
}

int main()
{
    string s;

    while (getline(cin, s)) {
        while (s.find("the") == string::npos || s.find("this") == string::npos || s.find("that") == string::npos) f(s);
        cout << s << endl;
    }
}