/**
     * QueueArray.java
     */
    package cn.edu.uibe.oop;
    /**
     * 数组实现的循环队列
     * @author TongQiang
     */
    public class QueueArray {
        Object[] a; //对象数组，队列最多存储a.length-1个对象
        int front;  //队首下标
        int rear;   //队尾下标
        public QueueArray(){
            this(10); //调用其它构造方法
        }
        public QueueArray(int size){
            a = new Object[size];
            front = 0;
            rear =0;
        }
        /**
         * 将一个对象追加到队列尾部
         * @param obj 对象
         * @return 队列满时返回false,否则返回true
         */
        public boolean enqueue(Object obj){
            if((rear+1)%a.length==front){
                return false;
            }
            a[rear]=obj;
            rear = (rear+1)%a.length;
            return true;
        }
        /**
         * 队列头部的第一个对象出队
         * @return 出队的对象，队列空时返回null
         */
        public Object dequeue(){
            if(rear==front){
                return null;
            }
            Object obj = a[front];
            front = (front+1)%a.length;
            return obj;
        }
        public static void main(String[] args) {
            QueueArray q = new QueueArray(4);
            System.out.println(q.enqueue(“张三”));
            System.out.println(q.enqueue(“李斯”));
            System.out.println(q.enqueue(“赵五”));
            System.out.println(q.enqueue(“王一”));//无法入队列，队列满
            for(int i=0;i<4;i++){
                System.out.println(q.dequeue());
            }
        }
    }