Language: C++

#include <iostream>
#include <string>

using namespce std;

int main() {
  string board[50];
  int H, W;
  cin >> H >> W;

  for(int i = 0; i < H; ++i) {
    cin >> board[i];
  }


  for(int i=0; i < H; ++i) {
    for(int j=0; j < W; ++j) {
      if(board[i][j] == '#') continue;

      int num = 0;
      for(int k = 0; k < 9; ++k) {
        int ni = i +k/3 -1;
        int nj = j +k%3 -1;
        if (ni < 0 || ni > H) continue;
        if (nj < 0 || nj > W) continue;
        if (board[ni][nj] == '#') ++num;
      }
      board[i][j] = char(num + '0');
    }
  }

  for(int i = 0; i < H; ++i) cout << board[i] << endl;


  return 0;

}

Compiler output:
a.cc:4:7: error: expected nested-name-specifier before 'namespce'
    4 | using namespce std;
      |       ^~~~~~~~
a.cc: In function 'int main()':
a.cc:7:3: error: 'string' was not declared in this scope
    7 |   string board[50];
      |   ^~~~~~
a.cc:7:3: note: suggested alternatives:
In file included from /usr/include/c++/14/iosfwd:41,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
In file included 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:
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:9:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    9 |   cin >> H >> W;
      |   ^~~
      |   std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:12:12: error: 'board' was not declared in this scope
   12 |     cin >> board[i];
      |            ^~~~~
a.cc:18:10: error: 'board' was not declared in this scope
   18 |       if(board[i][j] == '#') continue;
      |          ^~~~~
a.cc:26:13: error: 'board' was not declared in this scope
   26 |         if (board[ni][nj] == '#') ++num;
      |             ^~~~~
a.cc:28:7: error: 'board' was not declared in this scope
   28 |       board[i][j] = char(num + '0');
      |       ^~~~~
a.cc:32:30: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   32 |   for(int i = 0; i < H; ++i) cout << board[i] << endl;
      |                              ^~~~
      |                              std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:32:38: error: 'board' was not declared in this scope
   32 |   for(int i = 0; i < H; ++i) cout << board[i] << endl;
      |                                      ^~~~~
a.cc:32:50: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   32 |   for(int i = 0; i < H; ++i) cout << board[i] << endl;
      |                                                  ^~~~
      |                                                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~