使用数组模拟环形队列

package org.structure;

import java.util.Scanner;

/**
 * 环形队列模拟
 * @author cjj_1
 * @date 2020-08-03 13:43
 */
public class CircleArrayQueue {
    public static void main(String[] args) {
        CirleArray qa = new CirleArray(3);
        Scanner s = new Scanner(System.in);
        boolean loop = true;
        char key;
        while (loop) {
            System.out.println("s(show)：代表展示队列");
            System.out.println("a(add)：队列添加");
            System.out.println("g(get)：取出数据");
            System.out.println("f(print)：获取头");
            System.out.println("e(exit)：程序退出！");
            key = s.next().charAt(0);
            switch (key) {
                case 's':
                    qa.showQueue();
                    break;
                case 'a':
                    qa.addQueue(s.nextInt());
                    break;
                case 'g':
                    try {
                        System.out.println(qa.outOfQueue());//出队
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                    }

                    break;
                case 'f':
                    System.out.println(qa.getHead());
                    break;
                case 'e':
                    s.close();
                    loop = false;
                    break;
                default:
                    break;
            }
        }
    }
}
class CirleArray{
    private int front;
    private  int rear;
    private  int[] arr;
    private int maxSize;
    public CirleArray(int maxSize){
        this.maxSize = maxSize;
        front = 0;
        rear = 0;
        arr = new int[maxSize];
    }
    //栈是否满
    private boolean isFull(){
        return (rear+1) % maxSize == front;
    }
    //栈是否是空
    private boolean isEmpty(){
        return rear == front;
    }
    //栈是否是空
    private int getSize(){
        return (rear + maxSize - front) % maxSize;
    }
    //栈是否是空
    protected void addQueue(int n){
        if(isFull()){
            System.out.println("栈满了！");
            return;
        }
        arr[rear] = n ;
        System.out.println(arr[rear]);
        rear = (rear + 1)%maxSize;
    }
    //栈是否是空
    protected int outOfQueue(){
        if(isEmpty()){
            System.out.println("栈空了！！！");
            try {
                throw new Exception("您出现异常了");
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                return -1;
            }
        }
        int value = arr[front];
        front = (front +1 ) % maxSize;
        return value;
    }

    /**
     * 获取指针头
     * @return
     */
    protected int getHead(){
      return front;
    }
    /**
     * 获取指针头
     * @return
     */
    protected void showQueue(){
        if(isEmpty()){
            return;
        }
        for(int i =front;i< (front+getSize()); i++)
        {
            System.out.println(arr[i%maxSize]);
        }
    }
}