java - 如何阻止 do...while 循环无限

Question

我有以下代码，导致无限循环:

System.out.println("Adjust Invoices");
System.out.println("Would like to Pay an invoice or Add an invoice to your account?");
System.out.println("Press '1' to Pay and '2' to Add");

int invoice = choice.nextInt();
do
{
    if (invoice == 1)
    {
        System.out.println("one");
    }
    if (invoice == 2)
    {
        System.out.println("two");
    }
    else
    {
        System.out.println("Press '1' to Pay and '2' to Add");
    }
} while (invoice >= 3 || invoice <= 0);

当我输入“1”或“2”以外的内容时，如何阻止无限循环？

Answer 1

好吧，我想首先你必须把

int invoice = choice.nextInt();

在你的循环中以避免这种情况。否则使用循环就没有意义了。如果输入错误，你想循环，对吧？嗯，只有当您允许用户更正他们的输入时，这才有意义。

然后，一旦出现有效输入，我就会立即刹车，并将提示打印放在末尾，而无需“else”。另外，如果你在这些点上休息，你可以消除你的情况。这将是多余的。您的提示也是多余的，因此只需将其放在输入之前即可。 所以，你最终得到的是:

System.out.println("Adjust Invoices");
System.out.println("Would like to Pay an invoice or Add an invoice to your account?");

int invoice;
do
{
    System.out.println("Press '1' to Pay and '2' to Add");
    invoice = choice.nextInt();
    if (invoice == 1)
    {
        System.out.println("one");
        break;
    }
    if (invoice == 2)
    {
        System.out.println("two");
        break;
    }
} while (true);