求助

#include <iostream>
using namespace std;
int n, m, x = 0, y = 0, x2, y2;
char a[55][55];
int main(){
	cin >> n >> m;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			cin >> a[i][j];
			if (x == 0 && y == 0 && a[i][j] == '*') 
				x = i, y = j;
		}
	}
	bool flag = false;
	for(int i=n-1;i>-1;i--){
		for(int j=m-1;j>-1;j--){
			if (a[i][j] == '*') {
				x2 = i, y2 = j; 
				flag = true;
				break;
			}
		}
		if (flag) break;
		
	}
	for(int i=x;i<=x2;i++){
		for(int j=y;j<=y2;j++){
			cout << a[i][j];
		}
		cout << "\n";
	}
	return 0;
}