当用户输入负数 C++ 时中断循环

Question

执行一个循环，让用户输入两个将在函数中计算的输入。假设程序将继续运行，直到为价格或加价输入负数。价格或负标记的负数永远不会发送到 calcRetail 函数。

我的代码一直有效，直到我输入一个负数进行标记。循环继续。我错过了什么，以至于循环不仅在为价格输入负数时结束，而且在为标记输入负数时结束？

double calcRetail(double x = 0.0, double y = 0.0)
{
    double retail = x * (1 + (y / 100));
    return retail;
}
int main()
{
    double price = 0.0, markup = 0.0;
    while(price >= 0)
    {
        cout << "Enter the wholesale price of the item:" << endl;
        cin >> price;
        if(price >= 0)
        {
            cout << "Enter the percent markup of the item:" << endl;
            cin >> markup;

            cout << "$" << calcRetail(price,markup) << endl;
        }
    }

    return 0;
}

Answer 1

一些开发人员不赞成中断。像这样就可以了：

bool isLooping = true;
while (isLooping)
{
    cout << "Enter the wholesale price of the item:" << endl;
    cin >> price;

    if ( price >= 0 )
    {
        cout << "Enter the percent markup of the item:" << endl;
        cin >> markup;

        if (markup >= 0) cout << "$" << calcRetail(price,markup) << endl;
        else isLooping = false;
    }
    else isLooping = false;
}

Answer 2

这个怎么样？

while (true)
{
    cout << "Enter the wholesale price of the item:" << endl;
    cin >> price;

    if (price < 0) break;

    cout << "Enter the percent markup of the item:" << endl;
    cin >> markup;

    if (markup < 0) break;

    cout << "$" << calcRetail(price,markup) << endl;
}