Java boolean 条件while循环似乎忽略了if语句？

Question

在这附近 - if (code<10 || code>99)似乎是问题所在。当输入范围之外的数字时，循环会无限继续，似乎忽略了条件。我试过System.exit(0) ，虽然这完成了我想尝试使用 while 循环来停止代码的工作。

import java.util.*;
public class LockPicker {

    public static void main(String[] args) {
        Scanner kb = new Scanner(System.in);
        Random r = new Random();
        boolean stop = false; 
        while (!stop) {
            System.out.print("What is the unlock code? ");
            int code = kb.nextInt();
            if (code<10 || code>99) {
                System.out.println("Your number must be between 10 and 99");
                stop = !stop;
            }

            System.out.println("Picking the lock...");
            System.out.println("");
            int x = -1, counter = 0;
            while (x!=code) {
                x = r.nextInt(90)+10;
                System.out.println(x);
                counter++;
            }
            System.out.println("That took only "+counter+" tries to pick the lock!");
            stop = !stop;
        }
    }
}

Answer 1

您不需要 stop 变量。您可以使用break和 continue。

Random r = new Random();
while (true) {
    System.out.print("What is the unlock code? ");
    int code = kb.nextInt();
    if (code < 10 || code > 99) {
        System.out.println("Your number must be between 10 and 99");
        continue;
    }

    System.out.println("Picking the lock...");
    System.out.println("");
    int x = -1, counter = 0;
    while (x != code) {
        x = r.nextInt(90) + 10;
        System.out.println(x);
        counter++;
    }
    System.out.println("That took only " + counter
            + " tries to pick the lock!");
    break;
}

continue 将跳过迭代并转到 while 循环以再次提示用户输入数字。当找到匹配项时，break 将结束 while 循环。