队列的java实现

冷不防 2022-07-10 09:58 208阅读 0赞

和栈相反，队列是一种先进后出的数据结构

这里还是采用最简单的数组来实现和前面栈的实现比较类似，只是这里用了两个指针:

![Center][]

![Center 1][]

![Center 2][]

下面贴出代码：

package aa;
    
    public class Queue {
    	private Object[] data=null;
    	private int maxSize;//队列的大小
    	private int front;//队头
    	private int rear;//队尾
    	public Queue(int maxSize) {
    		super();
    		this.maxSize = maxSize;
    		data=new Object[maxSize];
    		front=rear=0;
    	}
    	//判断队列是否为空
    	public boolean isEmpty(){
    		return rear==front?true:false;
    	}
    	//插入元素
    	public boolean add(Object object){
    		if(rear==maxSize){
    			throw new RuntimeException("队列已满,无法插入元素!");
    		}
    		else{
    			data[rear++]=object;
    			return true;
    		}
    	}
    	//出队
    	public Object poll(){
    		if(isEmpty()){
    			throw new RuntimeException("队列为空!");
    		}
    		else{
    			return data[front++];
    		}
    	}
    	//返回队首元素
    	public Object peek(){
    		if(isEmpty()){
    			throw new RuntimeException("队列为空!");
    		}
    		else{
    			return data[front];
    		}
    		
    	}
    	//返回队尾元素
    	public Object end(){
    		if(isEmpty()){
    			throw new RuntimeException("队列为空!");
    		}
    		else{
    			return data[rear-1];
    		}
    		
    	}
    	//获取队列的长度
    	public int length(){
    		return rear;
    	}
    	public static void main(String[] args){
    		Queue q=new Queue(10);
    		q.add(1);
    		q.add(2);
    		q.add("pg");
    		q.add("sf");
    		q.add("pf");
    		q.add("sg");
    		q.add("c");
    		/*System.out.println(q.length());*/
    		for(int i=0;i<q.length();i++){
    			System.out.println(q.poll());
    		}
    	}
    }

[Center]: /images/20220709/58fc2d81a9a34f3db392529e3463a471.png
[Center 1]: /images/20220709/28319eee89db4fe0b303095157fde466.png
[Center 2]: /images/20220709/72af6177b00848e98920f2fa891bbbdb.png