Language: C++

int main(void) {
  int h, w;
  cin >> h >> w;
  
  string board[50];
  
  for (int i = 0; i < h; ++i) cin >> board[i];
  
  const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
  const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
  
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      if (board[i][j] == ’#’) continue;
      
      int num = 0;
      for (int d = 0; d < 8; ++ d) {
        const int ni = i + dy[d];
        const int nj = j + dx[d];
        
        if (ni < 0 or h <= ni) continue;
        if (nj < 0 or w <= nj) 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:14:26: error: extended character ’ is not valid in an identifier
   14 |       if (board[i][j] == ’#’) continue;
      |                          ^
a.cc:14:27: error: stray '#' in program
   14 |       if (board[i][j] == ’#’) continue;
      |                           ^
a.cc:14:28: error: extended character ’ is not valid in an identifier
   14 |       if (board[i][j] == ’#’) continue;
      |                            ^
a.cc:23:30: error: extended character ’ is not valid in an identifier
   23 |         if (board[ni][nj] == ’#’) num++;
      |                              ^
a.cc:23:31: error: stray '#' in program
   23 |         if (board[ni][nj] == ’#’) num++;
      |                               ^
a.cc:23:32: error: extended character ’ is not valid in an identifier
   23 |         if (board[ni][nj] == ’#’) num++;
      |                                ^
a.cc:26:32: error: extended character ’ is not valid in an identifier
   26 |       board[i][j] = char(num + ’0’);
      |                                ^
a.cc:26:32: error: extended character ’ is not valid in an identifier
a.cc: In function 'int main()':
a.cc:3:3: error: 'cin' was not declared in this scope
    3 |   cin >> h >> w;
      |   ^~~
a.cc:5:3: error: 'string' was not declared in this scope
    5 |   string board[50];
      |   ^~~~~~
a.cc:7:38: error: 'board' was not declared in this scope
    7 |   for (int i = 0; i < h; ++i) cin >> board[i];
      |                                      ^~~~~
a.cc:14:11: error: 'board' was not declared in this scope
   14 |       if (board[i][j] == ’#’) continue;
      |           ^~~~~
a.cc:14:26: error: '\U00002019' was not declared in this scope
   14 |       if (board[i][j] == ’#’) continue;
      |                          ^
a.cc:14:27: error: expected ')' before '\U00002019'
   14 |       if (board[i][j] == ’#’) continue;
      |          ~                ^~
      |                           )
a.cc:23:13: error: 'board' was not declared in this scope
   23 |         if (board[ni][nj] == ’#’) num++;
      |             ^~~~~
a.cc:23:30: error: '\U00002019' was not declared in this scope
   23 |         if (board[ni][nj] == ’#’) num++;
      |                              ^
a.cc:23:31: error: expected ')' before '\U00002019'
   23 |         if (board[ni][nj] == ’#’) num++;
      |            ~                  ^~
      |                               )
a.cc:26:7: error: 'board' was not declared in this scope
   26 |       board[i][j] = char(num + ’0’);
      |       ^~~~~
a.cc:26:32: error: '\U000020190\U00002019' was not declared in this scope
   26 |       board[i][j] = char(num + ’0’);
      |                                ^~~
a.cc:31:31: error: 'cout' was not declared in this scope
   31 |   for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                               ^~~~
a.cc:31:39: error: 'board' was not declared in this scope
   31 |   for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                       ^~~~~
a.cc:31:51: error: 'endl' was not declared in this scope
   31 |   for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                                   ^~~~