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:14:32: error: extended character ’ is not valid in an identifier
   14 |             if (board[i][j] == ’#’) continue;
      |                                ^
a.cc:14:33: error: stray '#' in program
   14 |             if (board[i][j] == ’#’) continue;
      |                                 ^
a.cc:14:34: error: extended character ’ is not valid in an identifier
   14 |             if (board[i][j] == ’#’) continue;
      |                                  ^
a.cc:23:38: error: extended character ’ is not valid in an identifier
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                                      ^
a.cc:23:39: error: stray '#' in program
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                                       ^
a.cc:23:40: error: extended character ’ is not valid in an identifier
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                                        ^
a.cc:26:38: error: extended character ’ is not valid in an identifier
   26 |             board[i][j] = char(num + ’0’);
      |                                      ^
a.cc:26:38: error: extended character ’ is not valid in an identifier
a.cc: In function 'int main()':
a.cc:3:5: error: 'cin' was not declared in this scope
    3 |     cin >> h >> w;
      |     ^~~
a.cc:5:5: error: 'string' was not declared in this scope
    5 |     string board[50];
      |     ^~~~~~
a.cc:7:40: error: 'board' was not declared in this scope
    7 |     for (int i = 0; i < h; ++i) cin >> board[i];
      |                                        ^~~~~
a.cc:14:17: error: 'board' was not declared in this scope
   14 |             if (board[i][j] == ’#’) continue;
      |                 ^~~~~
a.cc:14:32: error: '\U00002019' was not declared in this scope
   14 |             if (board[i][j] == ’#’) continue;
      |                                ^
a.cc:14:33: error: expected ')' before '\U00002019'
   14 |             if (board[i][j] == ’#’) continue;
      |                ~                ^~
      |                                 )
a.cc:23:21: error: 'board' was not declared in this scope
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                     ^~~~~
a.cc:23:38: error: '\U00002019' was not declared in this scope
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                                      ^
a.cc:23:39: error: expected ')' before '\U00002019'
   23 |                 if (board[ni][nj] == ’#’) num++;
      |                    ~                  ^~
      |                                       )
a.cc:26:13: error: 'board' was not declared in this scope
   26 |             board[i][j] = char(num + ’0’);
      |             ^~~~~
a.cc:26:38: error: '\U000020190\U00002019' was not declared in this scope
   26 |             board[i][j] = char(num + ’0’);
      |                                      ^~~
a.cc:31:33: error: 'cout' was not declared in this scope
   31 |     for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                 ^~~~
a.cc:31:41: error: 'board' was not declared in this scope
   31 |     for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                         ^~~~~
a.cc:31:53: error: 'endl' was not declared in this scope
   31 |     for (int i = 0; i < h; ++i) cout << board[i] << endl;
      |                                                     ^~~~