Language: C++

#include <iostream>
#include <string>
#include <string.h>
#include <map>
#include <set>
#include <vector>
#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cstdio>
using namespace std;
int main(){
string a;
int b=0;
cin>>a;
int c=a%100;
int d=(a-c)/10%10;
int e=(a-c-10*d)/100;
if(c==1)
b++;
if(d==1)
b++;
if(e==1)
b++;
cout<<b;
system("pause");
return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:8: error: no match for 'operator%' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'int')
   18 | int c=a%100;
      |       ~^~~~
      |       | |
      |       | int
      |       std::string {aka std::__cxx11::basic_string<char>}
a.cc:19:9: error: no match for 'operator-' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'int')
   19 | int d=(a-c)/10%10;
      |        ~^~
      |        | |
      |        | int
      |        std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/string:48,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 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:19:10: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   19 | int d=(a-c)/10%10;
      |          ^
/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:19:10: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   19 | int d=(a-c)/10%10;
      |          ^
a.cc:20:9: error: no match for 'operator-' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'int')
   20 | int e=(a-c-10*d)/100;
      |        ~^~
      |        | |
      |        | int
      |        std::string {aka std::__cxx11::basic_string<char>}
/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:20:10: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   20 | int e=(a-c-10*d)/100;
      |          ^
/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:20:10: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   20 | int e=(a-c-10*d)/100;
      |          ^