蒟蒻10分求助

#include<bits/stdc++.h>
using namespace std;


int main(){
	int n,m;
	cin>>n>>m;
	char a[n+1][m+1],b[n+1][m+1];
	for(int i=0;i<n;i++)
		for(int j=0;j<m;j++){
			cin>>a[i][j];
			if(a[i][j]=='*')b[i][j]=a[i][j];
			 else b[i][j]=='0';
		}
	int sum=0;
	for(int i=0;i<n;i++)
		for(int j=0;j<m;j++){
			if(a[i][j]=='*'){
				if(b[i+1][j]!='*')b[i+1][j]++;
				if(b[i+1][j+1]!='*')b[i+1][j+1]++;
				if(b[i][j+1]!='*')b[i][j+1]++;
				if(b[i-1][j]!='*')b[i-1][j]++;
				if(b[i-1][j-1]!='*')b[i-1][j-1]++;
				if(b[i][j-1]!='*')b[i][j-1]++;
				if(b[i+1][j-1]!='*')b[i+1][j-1]++;
				if(b[i-1][j+1]!='*')b[i-1][j+1]++;
			}
		}
		for(int i=0;i<n;i++)
		for(int j=0;j<m;j++)cout<<b[i][j];
	return 0;
}