Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

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

func incrementByte(b byte) byte {
	if b >= 97 && b < 122 {
		return b + 1
	} else if b == 122 {
		return 97
	}
	return b
}

func main() {
	scanner.Split(bufio.ScanLines)

	for {
		line := nextString()
		if len(line) == 0 {
			break
		}
		for i := 0; i <= 26; i++ {
			decoded := []byte{}
			for j := 0; j < len(line); j++ {
				decoded = append(decoded, incrementByte(line[j]))
			}
			line = string(decoded)
			if strings.Contains(line, "the") || strings.Contains(line, "this") || strings.Contains(line, "that") {
				fmt.Println(line)
				break
			}
		}
	}
}

C++: 
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <stack>
#include <cctype>
#include <complex>
#include <vector>
#include <algorithm>

using namespace std;


bool solve(){
	
	string s;
	while(getline(cin,s)){
		string str[26];
		int num;
		for(int i=0;i<26;i++){
			str[i] = s;
			for(int j=0;j<str[i].size();j++){
				for(int k=0;k<i;k++){
					if(str[i][j]=='.' || str[i][j]==' '){
						continue;
					}
					if(str[i][j] == 'a'){
						str[i][j] = 'z';
					}
					str[i][j]--; 
				}
			}
			
			for(int j=0;j<str[i].size();j++){
				string str_temp, str_temp2;	
				if(j+3 < str[i].size()){
					str_temp  = str[i].substr(j,3);
				}
				if(j+4 < str[i].size()){
					str_temp2 = str[i].substr(j,4);
				}
				if(str_temp=="the" || str_temp2=="this" || str_temp2=="that"){
					num = i;
				}
			}
		}
		
		
		cout<< str[num]<< endl;
	}		
	
	return true;
}

int main(){
	cout.setf(ios::fixed);
	cout.precision(10);
	solve();

	return 0;
}

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

int main(){
	string s, strCopy;
	while (getline(cin, s)) {
		for(int j=0 ; j<26 ; j++){
			for(int i=0 ; i<s.size() ; i++){
				if(s[i]>='a' && s[i]<='z'){
					s[i] = (s[i]=='z')? 'a' : s[i] + 1;
				}
			}
			if( s.find( "the" ) != string::npos || s.find( "this" ) != string::npos || s.find( "that" ) != string::npos){
				cout << s << endl;
			}
		}
	}
	
	return 0;
}

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

usinga namespace std;

void q17() {
	vector<string> hints;
	hints.push_back("the");
	hints.push_back("this");
	hints.push_back("that");

	vector< vector<string> > shiftHints;
	for (int i = 0; i < 26; i++) {
		vector<string> iShiftHints;
		for (int j = 0; j < hints.size(); j++) {
			string tmp = "";
			for (int k = 0; k < hints[j].length(); k++) {
				tmp += ((hints[j][k] - 'a' + i) % 26) + 'a';
			}
			iShiftHints.push_back(tmp);
		}
		shiftHints.push_back(iShiftHints);
	}

	string str;
	for (; getline(cin, str);) {
		int s;
		bool flag = false;
		for (s = 0; s < 26; s++) {
			for (int i = 0; i < hints.size(); i++) {
				if (str.find(shiftHints[s][i]) != -1) {
					flag = true;
				}
			}
			if (flag) break;
		}

		string ans = "";
		for (int i = 0; i < str.length(); i++) {
			ans += isalpha(str[i]) ? (str[i] - 'a' - s + 26) % 26 + 'a' : str[i];
		}
		cout << ans << endl;
	}
}

int main() {
	q17();
	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <cstdio>
#include <map>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,b) FOR(i,0,b)
#define PB push_back
#define MP make_pair
char rec(char x,int s){
  return x-s;
}
int main(){
  string s[80];
  int k=0,l=0;
  while(cin>>s[k]){
    int y=s[k][0]-'t';
    if(s[k].size()==3){
      if(rec(s[k][1],y)=='h'&&rec(s[k][2],y)=='e')l=y;
    }
    if(s[k].size()==4){
      if(rec(s[k][1],y)=='h'&&rec(s[k][2],y)=='a'&&rec(s[k][3],y)=='t')l=y;
      else if(rec(s[k][1],y)=='h'&&rec(s[k][2],y)=='i'&&rec(s[k][3],y)=='t')l=y;
    }
    k++;
  }
  for(int i=0;i<k;i++){
    for(int j=0;j<s[i].size();j++){
      if(s[i][j]=='.')cout<<'.';
      else cout<<rec(s[i][j],l);
    }
    if(i==k-1)cout<<endl;
    else cout<<" ";
  }
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<cstdio>
#include<climits>
#include<cmath>
#include<cstring>
#include<string>
#include<complex>
#include<iomanip>

#define EPS (1e-10)
using namespace std;
#define PI (3.1415926535)

int main(){
	int i;
	bool b = false;
	string str;
	string word[3] = {"the", "this", "that"};

	while(!b && getline(cin, str)){
		for(i = 0; i < 26 && !b; i++){
			for(int j = 0; j < str.size(); j++){
				if(str[j] >= 'a' && str[j] <= 'z'){
					str[j]++;
					if(str[j] > 'z'){
						str[j] -= 26;
					}
				}
			}
			for(int j = 0; j < 3; j++){
				if(str.find(word[j]) != -1){
					b = true;
					break;
				}
			}
		}
	}

	cout << str << endl;

	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]+26)%26=='t'-'h')&&(((s[i+1]-s[i+2]+26)%26==('h'-'e'+26)%26)||(((s[i+1]-s[i+2]+26)%26==('h'-'i'+26)%26)&&((s[i+2]-s[i+3]+26)%26==('i'-'s'+26)%26))||(((s[i+1]-s[i+2]+26)%26==('h'-'a'+26)%26)&&((s[i+2]-s[i+3]+26)%26==('a'-'t'+26)%26)))){
				for(int j=0;s[j]!='\0';j++){
					if((s[j]!=' ')&&(s[j]!='.')&&(s[j]!='\n')){
						putchar((s[j]+'t'-s[i]-'a'+26)%26+'a');
					}else{
						putchar(s[j]);
					}
				}cout<<endl;
				break;
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <cmath>
#include <cstdio>
#include <vector>

using namespace std;
string s;
char decrypt[50];
int key,i;

int main(){
    while(getline(cin,s)){
        const char *encrypt = s.c_str();
        while(encrypt[i] != '\0'){
            if(encrypt[i] - encrypt[i+1] == 12){
                key = 't' - encrypt[i];
                break;
            }
            i++;
        }

        i = 0;
        while(encrypt[i] != '\0'){
            if(encrypt[i] <= 'z' && encrypt[i] >= 'a'){
                decrypt[i] = (encrypt[i] - 'a' + key) % 26 + 'a';
            }
            else{
                decrypt[i] = encrypt[i];
            }
            i++;
        }
        printf("%s\n", decrypt);
    }
    return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <stdlib.h>
#include <vector>

using namespace std;


int main(){

	vector<string> str, ans;
	string temp;
	int slide;

	while(cin >> temp){
		str.push_back(temp);
	}

	for(int i=0 ; i<str.size() ; i++){
		ans.push_back(str[i]);
	}

	for(int i=0 ; i<25 ; i++){

		for(int j=0 ; j<str.size()-1 ; j++){
			for(int k=0 ; k<str[j].size() ; k++){
				str[j][k]++;
				if(str[j][k] > 'z'){
					str[j][k] = str[j][k] - 'z' + 'a' -1;
				}
			}
		}

		for(int k=0 ; k<str[str.size()-1].size()-1 ; k++){
			str[str.size()-1][k]++;
			if(str[str.size()-1][k] > 'z'){
				str[str.size()-1][k] = str[str.size()-1][k] - 'z' + 'a' -1;
			}
		}
		for(int k=0 ; k<str.size() ; k++){
			if(str[k] == "the" || str[k] == "that" || str[k] == "this"){
				slide = i;
				break;
			}
		}
	}

	for(int i=0 ; i<ans.size()-1 ; i++){
		for(int k=0 ; k<ans[i].size() ; k++){
			if((ans[i][k] + slide) > 'z'){
				ans[i][k] = ans[i][k] - 'z' + 'a' + slide;
			}
		}
		cout << ans[i] << ' ';
	}

	for(int i=0 ; i<ans[ans.size()-1].size() ; i++){
		if((ans[ans.size()-1][i] + slide) > 'z'){
			ans[ans.size()-1][i] = ans[ans.size()-1][i] - 'z' + 'a' +slide;
		}
	}
	cout << ans[ans.size()-1] << endl;

	return 0;
}