不开启o2优化错前四个测试点，开启后就过了，有大佬教教孩子吗

#include<iostream>

using namespace std;
int main() {
   char s[105][105];
   int a[105][105];
   int n, m;
   int c, d;
   cin >> n >> m;
   int i, j;
   for (i = 0; i < 105; i++)
   	for (j = 0; j < 105; j++)
   		a[i][j] = 0;
   for (i = 0; i < n; i++) {
   	for (j = 0; j < m; j++) {
   		cin >> s[i][j];
   	}
   }
   for (i = 0; i < n; i++) {
   	for (j = 0; j < m; j++) {
   		if (s[i][j] == '*') {
   			for (c = i - 1; c <= i + 1; c++)
   				for (d = j - 1; d <= j + 1; d++)
   					a[c][d]++;
   		}
   	}
   }
   for (i = 0; i < n; i++) {
   	for (j = 0; j < m; j++) {
   		if (s[i][j] == '*')
   			cout << s[i][j];
   		else
   			cout << a[i][j];
   	}
   	cout << endl;
   }
}