do
{
cout << "Enter the numerator and denominator of the first fraction: ";
cin >> a >> b;
cout << endl;
cout << "Enter the numerator and denominator of the second fraction: ";
cin >> c >> d;
cout << endl;
} while (!validNum(a, b, c, d));
...
bool validNum(int num1, int num2, int num3, int num4)
{
if (cin.fail() || num2 == 0 || num4 == 0)
{
if (num2 == 0 || num4 == 0)
{
cout << "Invalid Denominator. Cannot divide by 0" << endl;
cout << "try again: " << endl;
return false;
}
else
{
cout << "Did not enter a proper number" << endl;
cout << "try again: " << endl;
return false;
}
}
else
return true;
}
我想做的是确保分母不为零并且他们只输入数字。除以零代码工作正常,但是当您输入 char 值时,它会进入无限循环并且不知道为什么。有任何想法吗?
if (cin.fail() ... )
一旦您输入无效值(即char
),流中的故障位将打开并且validNum
总是返回 false,导致无限循环。
您需要在每次调用后清除错误状态并忽略其余输入:
if (std::cin.fail())
{
std::cin.clear();
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
}
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