如何实现循环以使程序再次要求用户输入而不是结束程序

Question

ans = JOptionPane.showInputDialog(null, "Enter amount to be withdrawn from checking");
double withCheck = Double.parseDouble (ans);
if (withCheck >= checking)
    {
    JOptionPane.showMessageDialog(null, "You do not have enough in your account for that.");
    }
else
    {
    double sum = checking - withCheck;
    JOptionPane.showMessageDialog(null, "Your checking balance is now: $" + sum + ", and your savings balance is: $" + savings);
    }
}

当前，这段代码在withCheck> = check时结束程序，我想知道一种使用某种循环再次询问该问题的方法，直到“ if”语句为假并可以继续else语句为止。

Answer 1

只需添加一个带有真实条件的while循环 ，并在某个条件变为真实时break它。

While(true)
{
    ans = JOptionPane.showInputDialog(null, "Enter amount to be withdrawn from checking");
    double withCheck = Double.parseDouble (ans);
    if (withCheck >= checking)
        {
        JOptionPane.showMessageDialog(null, "You do not have enough in your account for that.");
        }
    else
        {
        double sum = checking - withCheck;
        JOptionPane.showMessageDialog(null, "Your checking balance is now: $" + sum + ", and your savings balance is: $" + savings);
        break;
        }
    }
}