Language: C++

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

int main() {
 int N, p, a;
  string ans="a";
  vector<string> q = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
  if (N>=std::pow(27,10)) {
    for (int i = 0; i <11; i++) {
      a = std::pow(27,(10-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
   if ((N>=std::pow(27,9))&&(N<std::pow(27,10))) {
    for (int i = 0; i <10; i++) {
      a = std::pow(27,(9-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,8))&&(N<std::pow(27,9))) {
    for (int i = 0; i <9; i++) {
      a = std::pow(27,(8-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,7))&&(N<std::pow(27,8))) {
    for (int i = 0; i <8; i++) {
      a = std::pow(27,(7-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,6))&&(N<std::pow(27,7))) {
    for (int i = 0; i <7; i++) {
      a = std::pow(27,(6-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,5))&&(N<std::pow(27,6))) {
    for (int i = 0; i <6; i++) {
      a = std::pow(27,(5-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,4))&&(N<std::pow(27,5))) {
    for (int i = 0; i <5; i++) {
      a = std::pow(27,(4-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
 if ((N>=std::pow(27,3))&&(N<std::pow(27,4))) {
    for (int i = 0; i <4; i++) {
      a = std::pow(27,(3-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=std::pow(27,2))&&(N<std::pow(27,3))) {
    for (int i = 0; i <3; i++) {
      a = std::pow(27,(2-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27)&&(N<27*27)) {
    for (int i = 0; i <2; i++) {
      a = std::pow(27,(1-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=1)&&(N<27)) {
    ans = ans + q.at(N-1);
    cout << ans << endl;
  }
  cout << ans-ans.at(0) << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:82:14: error: no match for 'operator-' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'})
   82 |   cout << ans-ans.at(0) << endl;
      |           ~~~^~~~~~~~~~
      |           |         |
      |           |         __gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type {aka char}
      |           std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:618:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__y.base() - __x.base())) std::operator-(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  618 |     operator-(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:618:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__x.base() - __y.base())) std::operator-(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1790 |     operator-(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
In file included from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/complex:370:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const complex<_Tp>&)'
  370 |     operator-(const complex<_Tp>& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:370:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::complex<_Tp>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/complex:379:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const _Tp&)'
  379 |     operator-(const complex<_Tp>& __x, const _Tp& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:379:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::complex<_Tp>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/complex:388:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const _Tp&, const complex<_Tp>&)'
  388 |     operator-(const _Tp& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:388:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   mismatched types 'const std::complex<_Tp>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/complex:465:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&)'
  465 |     operator-(const complex<_Tp>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:465:5: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/valarray:1197:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__minus, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__minus, _Tp>::result_type> std::operator-(const valarray<_Tp>&, const valarray<_Tp>&)'
 1197 | _DEFINE_BINARY_OPERATOR(-, __minus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1197:1: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/valarray:1197:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__minus, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__minus, _Tp>::result_type> std::operator-(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1197 | _DEFINE_BINARY_OPERATOR(-, __minus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1197:1: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
   82 |   cout << ans-ans.at(0) << endl;
      |                       ^
/usr/include/c++/14/valarray:1197:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__minus, _Tp>::result_type> std::operator-(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1197 | _DEFINE_BINARY_OPERATOR(-, __minus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1197:1: note:   template argument deduction/substitution failed:
a.cc:82:23: note:   mismatched types 'const std::valarray<_Tp>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
   82 |   cout << ans-ans.at(0) << endl;
      |