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 <string>
#include <ctype.h>
using namespace std;

int main(){
    string before;
    while (getline(cin, before)) {
        int swich = 0;
        for (int i = 0; ; i++) {
            for (int j = 0; j < before.size(); j++) {
                if (before[j]>'z') {
                    before[j] = 'a';
                }
                else if (isalpha(before[j])) {
                    before[j]++;
                }
            }
            for (int j = 0; j < before.size(); j++) {
                if (before[j]=='t'&& before[j+1]=='h'&& before[j+2]=='e') {
                    swich = 1;
                    break;
                }
                else if (before[j]=='t'&&before[j+1]=='h'&&before[j+2]=='a'&&before[j+3]=='t') {
                    swich = 1;
                    break;
                }
                else if (before[j]=='t'&&before[j+1]=='h'&&before[j+2]=='i'&&before[j+3]=='s') {
                    swich = 1;
                    break;
                }
            }
            if (swich == 1) {
                break;
            }
        }
        cout << before << endl;
    }
    return 0;
}

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

using namespace std;

int main()
{
    string s;
    getline(cin, s);
    for (char &c: s) {
        if (islower(c)) {
            c = (c - 4 + 'z') % 'z';
        }
        cout << c;
    }
    cout << endl;
    return 0;
}

C++: #include <cmath>
#include <iostream>
#include <string>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <sstream>

using namespace std;

string decode(string inp,int n){
    string in=inp;
    for(int i=0;i<in.length();i++){
        if(isalpha(in[i])){
            in[i]=in[i]-n;
            if(in[i]<'a') in[i]+=('z'-'b');
        }
    }
    return in;
}
bool check(string inp){
    stringstream words(inp);
    string word;
    while(getline(words, word, ' ')){
        if(word=="the"||word=="this"||word=="that"||word=="the."||word=="this."||word=="that.")
            return true;
    }
    return false;
}

int main(){
    string input;
    while(getline(cin,input)){
        for(int i=0;i<26;i++){
            input=decode(input,1);
            if(check(input)){
                break;
            }
        }
        cout << input << endl;
    }
    return 0;
}

C++: #define _USE_MATH_DEFINES

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <utility>
#include <vector>
#include <numeric>

using namespace std;

int caesar(string s)
{
	string s0 = "this";
	string s1 = "that";
	string s2 = "the";

	for (int i = 0; i <= 26; i++)
	{
		if (s == s0 || s == s1 || s == s2 || s == s0+"." || s == s1 + "." || s == s2 + ".")
		{
			return i;
		}
		for (int j = 0; j < 4; j++)
		{
			s0.at(j) = s0.at(j)++;
			if (s0.at(j) > 'z')
			{
				s0.at(j) = 'a';
			}
			s1.at(j) = s1.at(j)++;
			if (s1.at(j) > 'z')
			{
				s1.at(j) = 'a';
			}
		}
		for (int j = 0; j < 3; j++)
		{
			s2.at(j) = s2.at(j)++;
			if (s2.at(j) > 'z')
			{
				s2.at(j) = 'a';
			}
		}
	}

	return -1;
}

int main()
{
	string str;
	for (; getline(cin, str);)
	{
		stringstream ss;
		ss << str;

		vector<string> w;
		string s;
		int c = -1;
		for (; ss >> s;)
		{
			w.push_back(s);
			
			if (c == -1)
			{
				c = caesar(s);
			}
		}

		for (int i = 0; i < w.size(); i++)
		{
			for (int j = 0; j < w.at(i).size(); j++)
			{
				if (w.at(i).at(j) != '.')
				{
					char sp = w.at(i).at(j) - c;
					if (sp < 'a')
					{
						int p = 'a' - sp - 1;
						w.at(i).at(j) = 'z' - p;
					}
					else
					{
						w.at(i).at(j) = sp;
					}
				}			
			}

			cout << w.at(i) << (i == w.size() - 1 ? "" : " ");
		}

		cout << endl;
	}
}

C++: #include <stdio.h>
#include <string.h>
int main()
{    char line[1000];
     int len,i;
    while(gets(line)){
         len=strlen(line);

         for(i=0;i<len;i++){
            if(line[i]>='a' && line[i]<='z'){
                if(line[i]=='a')printf("w");
                else if(line[i]=='b')printf("x");
                else  if(line[i]=='c')printf("y");
                else if(line[i]=='d')printf("z");
                else printf("%c",line[i]-4);}
                else printf("%c",line[i]);
}
printf("\n");

}

return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
using namespace std;
typedef pair<int, int> P;

string caesar(string s, int n){
    string res = s;
    rep(i, 0, s.size()){
        if('a' <= s[i] && s[i] <= 'z'){
            if(s[i] - 'a' + n < 26){
                res[i] += n;
            }else{
                res[i] += n - 26;
            }
        }
    }
    return res;
}

bool find(string s, string t){
    return s.find(t) != string::npos;
}

signed main(){
    string s;
    string str[3] = {"the", "this", "that"};
    while(getline(cin, s)){
        string t;
        bool f = false;
        rep(i, 0, 26){
            t = caesar(s, i);
            // cout << t << endl;
            rep(j, 0, 3){
                if(find(t, str[j])){
                    f = true;
                    i = 26;
                    break;
                }
            }
        }
        cout << t << endl;
    }
}

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

bool decision(string input){
	for(int i = 0; i < input.size()-3; i++){
		if((input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'e') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'i' && input[i+3] == 's') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'a' && input[i+3] == 't')){
			return true;
		}
	}
	return false;

}

int main(){
	string input;
	getline(cin, input);

	while(1){
		for(int i = 0; i < input.size(); i++){
			if('a' <= input[i] && input[i] <= 'z'){
				if(input[i] != 'z'){
					input[i] += 1;
				}else{
					input[i] = 'a';
				}
			}
		}
		if(decision(input)) break;
	}

	cout << input << endl;
	return 0;
}