Language: C++

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

int main() {
    int H,W;
    cin >> H >> W;
    string S[H][W];
    for(int i = 0; i < H; ++i) cin >> S[i];

    //*def vector
    const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
    const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};

    int num;
    for(int i = 0; i < H; ++i){
        for(int j = 0; j < W; ++j){
            //each cell
            if(S[i][j] == '#') continue;

            //count
            num = 0;
            //with vector
            for (int d = 0; d < 8; ++ d) {
                const int ni = i + dy[d];
                const int nj = j + dx[d];

                if(ni < 0 || H <= ni) continue;
                if(nj < 0 || W <= nj) continue;
                if(S[ni][nj] == '#') num++;
            }
            S[i][j] = char(num + '0');
            //for(int k = i-1; k <= i+1; ++k){
            //    if(k < 0 || k >= H) continue;
            //    for(int l = j-1; l <= j+1; ++l){
            //        if(l < 0 || l >= W) continue;
            //        if(S[k][l] == '#') num++;
            //    }
            //}
            //S[i][j] = '0' + num;
        }
    }
    for(int i = 0; i < H; ++i) cout << S[i] << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:36: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'std::string [W]' {aka 'std::__cxx11::basic_string<char> [W]'})
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                ~~~ ^~ ~~~~
      |                                |         |
      |                                |         std::string [W] {aka std::__cxx11::basic_string<char> [W]}
      |                                std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'std::string*' {aka 'std::__cxx11::basic_string<char>*'}
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'short int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(short int)((std::string*)(& S[i]))' to 'short int&'
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'short unsigned int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(short unsigned int)((std::string*)(& S[i]))' to 'short unsigned int&'
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(int)((std::string*)(& S[i]))' to 'int&'
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'unsigned int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(unsigned int)((std::string*)(& S[i]))' to 'unsigned int&'
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(long int)((std::string*)(& S[i]))' to 'long int&'
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long unsigned int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(long unsigned int)((std::string*)(& S[i]))' to 'long unsigned int&'
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long long int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(long long int)((std::string*)(& S[i]))' to 'long long int&'
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long long unsigned int' [-fpermissive]
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
      |                                          |
      |                                          std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:8:42: error: cannot bind rvalue '(long long unsigned int)((std::string*)(& S[i]))' to 'long long unsigned int&'
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:8:42: error: cannot bind non-const lvalue reference of type 'void*&' to an rvalue of type 'void*'
    8 |     for(int i = 0; i < H; ++i) cin >> S[i];
      |                                       ~~~^
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:25: note:   no known conversion for argument 1 from 'std::string [W]' {aka 'std::__cxx11::basic_string<char> [W]'} to 'float&'
  219 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  223 |       operator>>(double