链队(LinkdeQueue)

public class LinkQueue {
    private class Node {
        //数据
        int data;
        //指针(下一个结点)
        Node next;
        //无参构造函数,用于初始化
        public Node(){
        }
        //有参构造函数，用于初始化
        public Node(int data){
            this.data=data;
        }
    }

    //头节点
    private Node front;
    //尾节点
    private Node rear;
    //队列大小
    private int size;

    //无参构造函数
    public LinkQueue(){
        size = 0;
        front = null;
        rear = null;
    }

    //入队
    public void inQueue(int data){
        Node node = new Node(data);
        //空队列
        if(front == null){
            front = node;
            rear = front;
        }
        //队列不为空
        else{
            //后移
            rear.next = node;
            rear = node;
        }
        size++;
        System.out.println("入队成功");
    }

    //出队
    public void outQueue(){
        if(front == null){
            System.out.println("空队列");
            return;
        }
        else{
            int data = front.data;
            Node node = front;
            front = node.next;
            node = null;
            size--;
            System.out.println("出队成功");
        }
    }
    
    //清空队列
    public void clear(){
        Node node = front;
        while(node != null){
            front = node.next;
            node = null;
            node = front;
            size--;
        }
        front = null;
        rear = null;
        System.out.println("清队成功");
    }

    //输出
    public void show(){
        StringBuilder sb = new StringBuilder();
        if(front == null) {
            System.out.println("空队列");
            return;
        }
        else{
            Node node = front;
            while(node.next != null){
                sb.append(node.data+" ");
                node = node.next;
            }
            sb.append(node.data);
        }
        System.out.println(sb.toString());
        return;
    }
    
    public static void main(String[] args) {
        LinkQueue queue =new LinkQueue();
        queue.show();
        queue.inQueue(5);
        queue.inQueue(4);
        queue.inQueue(3);
        queue.inQueue(2);
        queue.inQueue(1);
        queue.show();
        queue.outQueue();
        queue.outQueue();
        queue.show();
        queue.clear();
        queue.show();
    }
}