c++ - 如果输入错误，我的程序如何停止复制

Question

我的程序将重复输出:“您目前位于5楼的2楼
码的总和为:7，码的乘积为:12
在他捕获你之前，再试一次!”
根据添加了多少个错误字符，我该如何解决？我已经插入了cin.clear和cin.ignore，但是它将重复上面的部分。

也就是说，如果我输入wasds，它将重复5倍。任何其他笔记也表示赞赏。

    #include <iostream>
#include <ctime>
using namespace std;

int PlayerLevel = 0;
int MaxLevel = 5;

bool GamePlay ()
{

srand(time(NULL));

int PlayerGuessA, PlayerGuessB, PlayerGuessC;

int CodeA = rand() % PlayerLevel + PlayerLevel;
int CodeB = rand() % PlayerLevel + PlayerLevel;
int CodeC = rand() % PlayerLevel + PlayerLevel;

int SumofCodes = CodeA + CodeB + CodeC;
int ProductofCodes = CodeA * CodeB * CodeC;

    cout << "You are currently on the " << PlayerLevel << " floor out of 5" << endl;
    cout << "The sum of the codes is: " << SumofCodes << " and the product of the codes is: " << ProductofCodes << endl;

    cin >> PlayerGuessA >> PlayerGuessB >> PlayerGuessC;



    int PlayerProduct = PlayerGuessA * PlayerGuessB * PlayerGuessC;
    int PlayerSum = PlayerGuessA + PlayerGuessB + PlayerGuessC;

    if (PlayerProduct == ProductofCodes && SumofCodes == PlayerSum) {
        cout << "Great Job you got this!!!\n" << endl;
        ++PlayerLevel;
        return true;
    } 
    else
    {
        cout << "Try again before he catches onto you!\n" << endl;
        return false;
    }

}


int GameStart()
{
    string Introduction = "Welcome to your worst nightmare. You are trapped in a murderer's house. You are on the 5th floor and need to get to the first floor to escape.\n";
    string Instructions = "He has each door locked behind a security system that requires a 3 number code to disarm it.\nEnter the codes and move foward. Each level will the code will be harder to figure out.\n";
    string PlayerStart;

    cout << Introduction << endl;
    cout << Instructions << endl;
    cout << "Would you like to escape? Yes or No" << endl;

    cin >> PlayerStart;

    if (!(PlayerStart != "Yes" && PlayerStart != "yes")) {
        ++PlayerLevel;
    }
    return 0;
}



int main ()
{

if (PlayerLevel == 0) {
    GameStart();
    }
while (PlayerLevel <= MaxLevel) 
{
    bool bLevelComplete = GamePlay();
    cin.clear ();
    cin.ignore();
}

cout << "You Made it out! Now run before he finds out!" << endl;
return 0;

}

Answer 1

当输入的类型与提取到的变量的类型不匹配时，cin将设置失败位。一旦发生这种情况，所有后续读取都会失败，直到重置流为止。令人讨厌的字符仍留在缓冲区中，因此也需要清除。
您对cin.clear()和cin.ignore()的使用意味着将重置故障位，但是仅删除一个有问题的字符(默认情况下cin.ignore()忽略一个字符)。这就是为什么您看到输出对x个错误字符重复了x次的原因。

您可以执行以下操作:

while (PlayerLevel <= MaxLevel) 
{
    bool bLevelComplete = GamePlay();
    if (cin.fail())
    {
        //Input extraction failed, need to reset stream and clear buffer until newline
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(),'\n');

    }
}