我如何让我的部分代码循环并重复一个问题，直到答案是有效的输入C++

How do I get part of my code to loop and repeat a question until the answer is a valid input C++

本文关键字：问题 一个 答案 输入 C++ 有效 我的部 代码 循环      更新时间：2023-10-16

代码运行良好，我只是缺少一个元素，如果结尾要求重复游戏，如果我作为用户输入"a"，我希望代码用一个新的cout语句重复这个问题，例如"无效答案，请回答y/n，如果是，显然游戏会重新启动(摇滚剪刀游戏b/w 2名玩家)

int main(int argc, const char * argv[]) {
char playAgain ='y' ;  // loop control

do
{
char Player1;
char Player2 = '';

cout << "Player 1, Enter R, P, or S: ";         // Player 1
cin >> Player1;
Player1 = toupper(Player1);
while (Player1 != 'R' && Player1 != 'P' && Player1 !='S' )
{
cout << "please only answer R , P , or S: " << endl;
cin >> Player1;
Player1 = toupper(Player1);

}
{
cout << "Player 2, Enter R, P, or S: ";         // Player 2
cin >> Player2;
Player2 = toupper(Player2);
while (Player2 != 'R' && Player2 != 'P' && Player2 !='S' )
{
cout << "please only answer R , P , or S: " << endl;
cin >> Player2;
Player2 = toupper(Player2);
}}
if (Player1 == Player2)     //TIE
{
cout << "Nobody wins."<<endl;}

else   if (Player1 == 'R' && Player2 == 'P')
{
cout << "Paper covers rock, Player 2 wins."<< endl;
}
else if (Player1 == 'P' && Player2 == 'R')
{
cout << "Paper covers rock, Player 1 wins."<< endl;
}
else  if (Player1 == 'S' && Player2 == 'P')
{
cout << "Scissors cut paper, Player 1 wins."<< endl;
}
else  if (Player1 == 'P' && Player2 == 'S')
{
cout << "Scissors cut paper, Player 2 wins."<< endl;
}
else if (Player1 == 'R' && Player2 == 'S')
{
cout << "Rock breaks scissors, Player 1 wins."<< endl;
}
else if (Player1 == 'S' && Player2 == 'R')
{
cout << "Rock breaks scissors, Player 2 wins."<< endl;
}
{     cout << "Play again? (y/n): ";         // Player 1
cin >> playAgain;
if (playAgain=='N' || playAgain=='n')
{ cout <<"BYEEEEE"<<endl;}
}}

while (playAgain=='Y' || playAgain=='y');
return 0;
}

我相信最优雅的方法是这样做：

#include <iostream>
#include <string>
#include <set>
static const std::set<std::string> RPS {
"R",
"P",
"S"
};
static const std::set<std::string> yesno {
"yes",
"no"
};
std::string ask_user(
const std::string& question,
const std::set<std::string>& valid_answers
) {
std::cout << question << std::flush; // outputs question (and flushes cout so it displays)
std::string answer;
while (true) { // this loop will terminate only when "break;" is reached
std::getline(std::cin, answer); // get answer
if (valid_answers.count(answer) == 0) { // if answer is not in valid_answers
std::cout << "Invalid answer!" << std::endl; // complain to the user
} else { // if answer is not invalid
break; // exit loop
}
}
return answer;
}

然后你可以要求这样的行动：

std::string p1_move = ask_user("Player 1 move (R/P/S)?n", RPS);

或者像这样的是/否答案：

std::string answer = ask_user("Another game (yes/no)?n", yesno);

这将防止您在要求用户移动和要求用户玩另一个游戏时重复代码，因此这是更好的代码练习。

您可以这样做：

int main() {
while(true) {
char input;
std::cout << "Would you like to continue the game? (y/n): ";
std::cin >> input;
if(input == 'n' || input == 'N')
return 0;
else if(input == 'y' || input == 'Y') {
startGame();
break;
} else {
std::cout << "Invalid response." << std::endl;
}
}
}

cout << "Play again? (y/n): ";
cin >> playAgain;
while (playAgain != 'Y' && playAgain != 'y' && playAgain !='n' )
{     cout << "Error input :Play again? (y/n): ";         // Player 1
cin >> playAgain;

^想明白了！是的，回到我的压痕，并与我的第一个循环进行了比较。非常感谢大家的帮助：)

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