什么结构体？给我坐下

有个大坑，如果找不到自己的账号，得输出empty

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main(){
	string a;
	cin >> a;
	int n;
	cin >> n;
    bool flag = 0;//***
	for(int i = 1; i <= n; i++){
		string yhm, mima, x;
		cin >> yhm >> mima >> x;
		if(x == a){
                        flag = 1;//***
			cout << yhm << ' ';
			for(int j = 0; j < mima.length(); j++){
				if('a' <= mima[j] && mima[j] <= 'z') cout << char(mima[j] - 32);
				else if('A' <= mima[j] && mima[j] <= 'Z') cout << char(mima[j] + 32);
				else cout << mima[j];
			}cout << endl;
		}
	}if(!flag) cout << "empty";//超级大坑！！！

	return 0;
}