Language: C++

//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <queue>
#include <iterator>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;
using namespace string;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int gcd(int a, int b){
   int tmp;
   while(a%b==0){
      tmp=a%b;
      a=b;
      b=tmp;
   }
}

int lcm(int a,int b){
   return a*b/gcd(a,b);
}

bool prime_number(int n){
   if(n < 2){
      return false;
   }
   else if(n == 2){
      return true;
   }
   if(n % 2 == 0){
      return false;
   }
   for(int i=3;i<=n/i;i+=2){
      if(n % i == 0) return false;
      return true;
   }
}

int main(){
   string a;

   while(getline(cin,a)){
      while(a.find("the")==npos&&a.find("this")==npos&&str.find("that")==npos)
         REP(i,a.size()){
            if(a[i]=='z') a[i]=='a';
            else if(a[i]>=a&&a[i]<='z') a[i]++;
         }
      cout << a << endl;
   }
   return 0;
}

Compiler output:
a.cc:28:17: error: 'string' is not a namespace-name
   28 | using namespace string;
      |                 ^~~~~~
a.cc: In function 'int gcd(int, int)':
a.cc:82:1: warning: no return statement in function returning non-void [-Wreturn-type]
   82 | }
      | ^
a.cc: In function 'int main()':
a.cc:108:28: error: 'npos' was not declared in this scope
  108 |       while(a.find("the")==npos&&a.find("this")==npos&&str.find("that")==npos)
      |                            ^~~~
a.cc:108:56: error: 'str' was not declared in this scope; did you mean 'std'?
  108 |       while(a.find("the")==npos&&a.find("this")==npos&&str.find("that")==npos)
      |                                                        ^~~
      |                                                        std
a.cc:111:25: error: no match for 'operator>=' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/vector:62,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_pair.h:1070:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator>=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1070 |     operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1070:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::pair<_T1, _T2>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:476:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  476 |     operator>=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:476:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
/usr/include/c++/14/bits/stl_iterator.h:520:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  520 |     operator>=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:520:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1724 |     operator>=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::move_iterator<_IteratorL>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1781 |     operator>=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::move_iterator<_IteratorL>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/vector:66:
/usr/include/c++/14/bits/stl_vector.h:2114:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator>=(const vector<_Tp, _Alloc>&, const vector<_Tp, _Alloc>&)'
 2114 |     operator>=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:2114:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::vector<_Tp, _Alloc>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/vector:87:
/usr/include/c++/14/tuple:2631:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator>=(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2631 |     operator>=(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2631:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::tuple<_UTypes ...>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/list:65,
                 from a.cc:4:
/usr/include/c++/14/bits/stl_list.h:2217:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator>=(const __cxx11::list<_Tp, _Alloc>&, const __cxx11::list<_Tp, _Alloc>&)'
 2217 |     operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_list.h:2217:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::__cxx11::list<_Tp, _Alloc>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/map:63,
                 from a.cc:5:
/usr/include/c++/14/bits/stl_map.h:1578:5: note: candidate: 'template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator>=(const map<_Key, _Tp, _Compare, _Allocator>&, const map<_Key, _Tp, _Compare, _Allocator>&)'
 1578 |     operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_map.h:1578:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::map<_Key, _Tp, _Compare, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/map:64:
/usr/include/c++/14/bits/stl_multimap.h:1200:5: note: candidate: 'template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator>=(const multimap<_Key, _Tp, _Compare, _Allocator>&, const multimap<_Key, _Tp, _Compare, _Allocator>&)'
 1200 |     operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_multimap.h:1200:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::multimap<_Key, _Tp, _Compare, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/set:63,
                 from a.cc:6:
/usr/include/c++/14/bits/stl_set.h:1053:5: note: candidate: 'template<class _Key, class _Compare, class _Alloc> bool std::operator>=(const set<_Key, _Compare, _Allocator>&, const set<_Key, _Compare, _Allocator>&)'
 1053 |     operator>=(const set<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_set.h:1053:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::set<_Key, _Compare, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/set:64:
/usr/include/c++/14/bits/stl_multiset.h:1039:5: note: candidate: 'template<class _Key, class _Compare, class _Alloc> bool std::operator>=(const multiset<_Key, _Compare, _Allocator>&, const multiset<_Key, _Compare, _Allocator>&)'
 1039 |     operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_multiset.h:1039:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::multiset<_Key, _Compare, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |             else if(a[i]>=a&&a[i]<='z') a[i]++;
      |                           ^
In file included from /usr/include/c++/14/deque:66,
                 from a.cc:7:
/usr/include/c++/14/bits/stl_deque.h:2363:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator>=(const deque<_Tp, _Alloc>&, const deque<_Tp, _Alloc>&)'
 2363 |     operator>=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_deque.h:2363:5: note:   template argument deduction/substitution failed:
a.cc:111:27: note:   mismatched types 'const std::deque<_Tp, _Alloc>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
  111 |