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:13:23: error: extended character ’ is not valid in an identifier
   13 |    if (board[i][j] == ’#’) continue;
      |                       ^
a.cc:13:24: error: stray '#' in program
   13 |    if (board[i][j] == ’#’) continue;
      |                        ^
a.cc:13:25: error: extended character ’ is not valid in an identifier
   13 |    if (board[i][j] == ’#’) continue;
      |                         ^
a.cc:22:25: error: extended character ’ is not valid in an identifier
   22 |    if (board[ni][nj] == ’#’) num++;
      |                         ^
a.cc:22:26: error: stray '#' in program
   22 |    if (board[ni][nj] == ’#’) num++;
      |                          ^
a.cc:22:27: error: extended character ’ is not valid in an identifier
   22 |    if (board[ni][nj] == ’#’) num++;
      |                           ^
a.cc:25:29: error: extended character ’ is not valid in an identifier
   25 |    board[i][j] = char(num + ’0’);
      |                             ^
a.cc:25:29: error: extended character ’ is not valid in an identifier
a.cc: In function 'int main()':
a.cc:3:2: error: 'cin' was not declared in this scope
    3 |  cin >> h >> w;
      |  ^~~
a.cc:5:2: error: 'string' was not declared in this scope
    5 |  string board[50];
      |  ^~~~~~
a.cc:7:37: error: 'board' was not declared in this scope
    7 |  for (int i = 0; i < h; ++i) cin >> board[i];
      |                                     ^~~~~
a.cc:13:8: error: 'board' was not declared in this scope
   13 |    if (board[i][j] == ’#’) continue;
      |        ^~~~~
a.cc:13:23: error: '\U00002019' was not declared in this scope
   13 |    if (board[i][j] == ’#’) continue;
      |                       ^
a.cc:13:24: error: expected ')' before '\U00002019'
   13 |    if (board[i][j] == ’#’) continue;
      |       ~                ^~
      |                        )
a.cc:22:8: error: 'board' was not declared in this scope
   22 |    if (board[ni][nj] == ’#’) num++;
      |        ^~~~~
a.cc:22:25: error: '\U00002019' was not declared in this scope
   22 |    if (board[ni][nj] == ’#’) num++;
      |                         ^
a.cc:22:26: error: expected ')' before '\U00002019'
   22 |    if (board[ni][nj] == ’#’) num++;
      |       ~                  ^~
      |                          )
a.cc:25:4: error: 'board' was not declared in this scope
   25 |    board[i][j] = char(num + ’0’);
      |    ^~~~~
a.cc:25:29: error: '\U000020190\U00002019' was not declared in this scope
   25 |    board[i][j] = char(num + ’0’);
      |                             ^~~
a.cc:30:32: error: 'cout' was not declared in this scope
   30 |    for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                ^~~~
a.cc:30:40: error: 'board' was not declared in this scope
   30 |    for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                        ^~~~~
a.cc:30:52: error: 'endl' was not declared in this scope
   30 |    for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                                    ^~~~