Language: C++

        #include <bits/stdc++.h>
        using namespace std;
         
        int main() {
          string s1, s2, s3;
          int count = 0;
          cin >> s1 >> s2 >> s3;
          for ( i = 0 ; i <= 3 ; i++){
          	if(s1 || s2 || s3 === '1'){
              count++;
            }
          }
          cout <<  count << endl;
        }

Compiler output:
a.cc: In function 'int main()':
a.cc:8:17: error: 'i' was not declared in this scope
    8 |           for ( i = 0 ; i <= 3 ; i++){
      |                 ^
a.cc:9:23: error: no match for 'operator||' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
    9 |                 if(s1 || s2 || s3 === '1'){
      |                    ~~ ^~ ~~
      |                    |     |
      |                    |     basic_string<[...]>
      |                    basic_string<[...]>
a.cc:9:23: note: candidate: 'operator||(bool, bool)' (built-in)
    9 |                 if(s1 || s2 || s3 === '1'){
      |                    ~~~^~~~~
a.cc:9:23: note:   no known conversion for argument 2 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'bool'
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166,
                 from a.cc:1:
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:9:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
    9 |                 if(s1 || s2 || s3 === '1'){
      |                          ^~
a.cc:9:37: error: expected primary-expression before '=' token
    9 |                 if(s1 || s2 || s3 === '1'){
      |                                     ^