Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {

  int H,W;
  
  cin>>H>>W;
  
  string s[H];
  
  for(int i=0;i<H;i++)
  {
     cin>>s[i];
  }
  
  for(int i=0;i<H;i++)
  {
  for(int j=0;j<W;j++)
    {
        int sum=0;
        if(s[i]s.at(j)=='.')
        {
           for(int x=i-1;x<=i;x++)
           {
              for(int y=j-1;y<j+1;j++)
              {
                  if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
                  {
                     sum++;
                  }
              }
           }
         s[i].at(j)=sum;
        }
    }
  }
     for(int i=0;i<H;i++)
     {
       cout<<s[i]<<endl;
     }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:16: error: expected ')' before 's'
   22 |         if(s[i]s.at(j)=='.')
      |           ~    ^
      |                )
a.cc:22:15: error: could not convert 's[i]' from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'bool'
   22 |         if(s[i]s.at(j)=='.')
      |            ~~~^
      |               |
      |               std::string {aka std::__cxx11::basic_string<char>}
a.cc:28:42: error: no match for 'operator&&' (operand types are 'bool' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                      ~~~~~~~~~~~~~~~~~~~~^~~~~~
      |                                     |         |
      |                                     bool      std::string {aka std::__cxx11::basic_string<char>}
a.cc:28:42: note: candidate: 'operator&&(bool, bool)' (built-in)
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                      ~~~~~~~~~~~~~~~~~~~~^~~~~~
a.cc:28:42: 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:415:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__logical_and, typename _Dom1::value_type>::result_type> std::operator&&(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  415 |     _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:415:5: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'bool'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:415:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_and, typename _Dom1::value_type>::result_type> std::operator&&(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  415 |     _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:415:5: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'bool'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:415:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_and, typename _Dom1::value_type>::result_type> std::operator&&(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  415 |     _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:415:5: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:415:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_and, typename _Dom1::value_type>::result_type> std::operator&&(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  415 |     _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:415:5: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'bool'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:415:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_and, typename _Dom1::value_type>::result_type> std::operator&&(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  415 |     _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:415:5: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/valarray:1206:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_and, _Tp>::result_type> std::operator&&(const valarray<_Tp>&, const valarray<_Tp>&)'
 1206 | _DEFINE_BINARY_OPERATOR(&&, __logical_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1206:1: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   mismatched types 'const std::valarray<_Tp>' and 'bool'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/valarray:1206:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__logical_and, _Tp>::result_type> std::operator&&(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1206 | _DEFINE_BINARY_OPERATOR(&&, __logical_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1206:1: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   mismatched types 'const std::valarray<_Tp>' and 'bool'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
/usr/include/c++/14/valarray:1206:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_and, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_and, _Tp>::result_type> std::operator&&(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1206 | _DEFINE_BINARY_OPERATOR(&&, __logical_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1206:1: note:   template argument deduction/substitution failed:
a.cc:28:47: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                                               ^
a.cc:28:48: error: expected ')' before 's'
   28 |                   if(x>=0&&x<H&&y>=0&&y<W&&s[x]s.at(y)=='#')
      |                     ~                          ^
      |                                                )