杭电OJ2024

#include <iostream>#include <string>using namespace std;int main(){int n;string s;cin >> n;cin.ignore(); //getchar();  读入后面键入的回车 bool flag;for(int i = 0; i < n; i++){flag = true;s= "";getline(cin, s);//C++读入带空格的字符串 ， 和上面的注释联合看 if(s[0] == '_' || (s[0] >= 'a' && s[0] <= 'z') || (s[0] >= 'A' && s[0] <= 'Z')){for(string::size_type i = 1 ; i < s.size(); i++){if(s[i] == '_' || (s[i] >= '0' && s[i] <= '9') || (s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z')){}//如果是对的什么也不做 else{flag = false;}}}else{flag = false;}//if-(if-else)-elseif(flag){cout << "yes" << endl;}else{cout << "no" << endl;}}return 0;}