求助为什么通过不了//只有20分，谢谢！！

#include <iostream>
using namespace std;
const int N = 105;
int ans = 0;
char a[N][N];
int n, m;
int main () {
    cin >> n >> m;
    for (int i = 0; i <= n + 1; i++) {
        a[0][i] = '?';
        a[i][0] = '?';
        a[n][i] = '?';
        a[i][n] = '?';
    }
    for (int i = 1; i <= n; i++) 
        for (int j = 1; j <= m; j++)
            cin >> a[n][m];
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= m; j++){
            if (a[i][j] == '*'){
                cout << '*';
            }
            else{
                if (a[i - 1][j - 1] == '*') ans++;
                if (a[i][j + 1] == '*') ans++;
                if (a[i][j - 1] == '*') ans++;
                if (a[i + 1][j] == '*') ans++;
                if (a[i + 1][j + 1] == '*') ans++;
                if (a[i + 1][j - 1] == '*') ans++;
                if (a[i - 1][j] == '*') ans++;
                if (a[i - 1][j + 1] == '*') ans++;
                cout << ans; 
                ans = 0;
            }
        }
        cout << endl;
    }    
    return 0;
}