Java：Switch案例

Question

所以我有一个简单的Queue实现，我一直试图为它做一个switch case语句。现在它工作得很好。我的问题是它会询问你是否要继续，但即使你按下＆＃34; n＆＃34; for＆＃34; No＆＃34;它仍将继续。

另一件事是我无法在case3中用随机数填充数组。

代码： 实施：

class Que{

    private int size;
    private int front = -1;
    private int rear = -1;
    private Integer[] queArr;

    public Que(int size) {
        this.size = size;
        queArr = new Integer[size];
    }
    public void insert(int item) {
        if(rear == size-1) {
            System.out.println("queue is overflowing");
        }
        else if(front==-1) {
            rear++;
            queArr[rear] = item;
            front = rear;
        }
        else {
            rear++;
            queArr[rear] = item;
        }
    }
    public void delete() {
        if(front == -1) {
            System.out.println("queue is underflow");
        }
        else if(front==rear) {
            System.out.println("removing "+queArr[front]);
            queArr[front] = null;
            front--;
            rear--;
        }
        else {
            System.out.println("removing "+queArr[front]);

            queArr[front] = null;

            for(int i=front+1;i<=rear;i++) {
                queArr[i-1]=queArr[i];
            }
            rear--;
        }

    }
    public void display() {
        if(front==-1)
            System.out.println("queue is empty");
        else
        {
            System.out.println("queue is:");
            for(int i=front;i<=rear;i++) {
                System.out.print(queArr[i]+"\t");
            }
        }
    }
}

测试：

import java.util.Random;

import java.util.Scanner;

public class TestQueue {

public static void main(String[] args) {

    System.out.println("Hi user!");

    Scanner scan = new Scanner(System.in);

    System.out.println("please enter size of queue array");

    int size = scan.nextInt();

    Que que = new Que(size);

    char ch;

    do{

        System.out.println("\nQueue operations \n");

        System.out.println("1. insert");

        System.out.println("2. delete");

        System.out.println("3. random");

        int choice = scan.nextInt();

        switch(choice)

        {

            case 1: System.out.println("enter integer element to insert");

                que.insert(scan.nextInt());

                break;

            case 2:que.delete();

                break;

            case 3:  Random rand = new Random();

                rand.nextInt(size);

                break;

        }

        que.display();

        System.out.println("\nDo you want to continue (Type y or n) \n");

        ch = scan.next().charAt(0);

    }

    while(ch!='N' || ch!='n');

}

}

我还需要一些关于如何读出和显示数组中所有素数的指针。但这可能是不同讨论的主题。

我想我在测试结束时搞砸了while语句。

Answer 1

while(ch!='N' || ch!='n');

始终为true（对于ch的任何值）。

你需要

 while(!(ch=='N' || ch=='n'));