キュー----リンクリスト実装キュー

/**
 *  
 */
package com.szy.structure.queues;

import java.util.Scanner;

class Node
{
	public int data;
	public Node next;
}
public class LinkedQueue
{
	Node FRONT,REAR;
	
	public LinkedQueue()
	{
		FRONT=null;
		REAR=null;
	}
	/**
	 *  
	 * @param element
	 */
	public void insert(int element)
	{
		Node newNode=new Node();
		newNode.data=element;
		newNode.next=null;
		if (FRONT==null)
		{
			FRONT=newNode;
			REAR=newNode;
		}
		else
		{
			REAR.next=newNode;
			REAR=newNode;
		}
	}
	/**
	 *  
	 */
	public void remove()
	{
		if (FRONT==null)
		{
			System.out.println(" ！");
			return;
		}
		FRONT=FRONT.next;
	}
	/**
	 *  
	 */
	public void display()
	{
		if (FRONT==null)
		{
			System.out.println(" ！");
			return;
		}
		Node currentNode=FRONT;
		while(currentNode!=null)
		{
			System.out.print(currentNode.data+" ");
			currentNode=currentNode.next;
		}
	}
	
	public static void main(String[] args) throws Exception {
		LinkedQueue queues=new LinkedQueue();
		int choice=0;
		while(true)
		{
			System.out.println("
---MENU---");
			System.out.println("1.Insert");
			System.out.println("2.Delete");
			System.out.println("3.Display");
			System.out.println("4.Exit");
			System.out.println("----------");
			System.out.println(" ：");
			Scanner scanner=new Scanner(System.in);
			choice=scanner.nextInt();
			switch (choice) {
			case 1:
			{
				System.out.println(" ：");
				int input=scanner.nextInt();
				queues.insert(input);
			}
				break;
			case 2:
			{
				queues.remove();
			}
			break;
			case 3:
			{
				queues.display();
			}
			break;
			case 4:
				return;
			default:
				System.err.println(" ！");
				break;
			}
		}
	}
}