这次我用了个新方法

#include <bits/stdc++.h>
using namespace std;
bool check(char c){
    if(c == 'Y' or c == 'y'){
        return true;
    }else{
        return false;
    }
}
int main(){
	char c;
    cin >> c;
    bool flag = check(c);
    if(flag == true){
        cout << "Yes";
    }else{
        cout << "No";
    }
    return 0;
}