算法学习(五)---队列

package com.tw.dst.sq;


/**
 * <p>队列是一种先进先出（FIFO）的线性数据结构，常用操作有插入（insert）和删除（remove）</p>
 * @author tangw 2010-11-27
 */
public class Queue {
	//	队列数组   
    private long queueArr[];   
    //队列的前端下标   
    private int front;   
    //队列的尾端下标   
    private int rear;   
    //队列的大小   
    private int maxSize;   
    //队列中元素的个数   
    private int nItems;   
    //初始化一个大小为size的队列   
    public Queue(int size){   
        queueArr = new long[size];   
        maxSize = size;   
        front = 0;   
        rear = -1;   
        nItems = 0;   
    }   
    //插入操作   
    public void insert(long value){   
        //队列已满   
        if(rear == maxSize-1)   
            rear = -1;   
        queueArr[++rear] = value;   
        nItems++;   
    }   
    //删除操作   
    public long remove(){   
        long temp = queueArr[front++];   
        if(front == maxSize)   
            front = 0;   
        nItems--;   
        return temp;   
    }   
    //返回队列第一个元素   
    public long peakFront(){   
        return queueArr[front];   
    }   
    //判断是否为空   
    public boolean isEmpty(){   
        return nItems == 0;   
    }   
    //判断是否已满   
    public boolean isFull(){   
        return nItems == maxSize;   
    }   
    //返回队列中元素的个数   
    public int size(){   
        return nItems;   
    }   
       
    public void print(){   
        for(int i = front;i < front+nItems;i++){   
            System.out.print(queueArr[i]+" ");   
        }   
        System.out.println();   
    }   
       
    public static void main(String[] args) {   
        Queue q = new Queue(10);   
        while(!q.isFull()){   
            long value = (long)(Math.random()*100);   
            q.insert(value);   
        }   
        q.print();   
        while(!q.isEmpty()){   
            q.remove();   
            q.print();   
        }   
        q.print();   
        System.out.println(q.isEmpty());   
    } 

}