Day17-CFANZ编程社区

1.代码：

package yrx;

public class LinkedQueue {
	/**
	 * An inner class.
	 */
	class Node {
		/**
		 * The data
		 */
		int data;

		/**
		 * The reference to the next node.
		 */
		Node next;

		/**
		 ****************
		 * The constructor.
		 *
		 * @param paraValue The data.
		 *****************
		 */
		public Node(int paraValue) {
			data = paraValue;
			next = null;
		}// Of the constructor
	}// Of class Node

	/**
	 * The header of queue.
	 */
	Node header;

	/**
	 * The tail of the queue.
	 */
	Node tail;

	/**
	 **************
	 * Construct an empty sequential list.
	 **************
	 */
	public LinkedQueue() {
		header = new Node(-1);
		// header.next=null;构造函数里已经有了，不用再写

		tail = header;
	}// Of the first constructor

	/**
	 **********************
	 * Enqueue.
	 *
	 * @param paraValue The value of the new node.
	 **********************
	 */
	public void enqueue(int paraValue) {
		Node tempNode = new Node(paraValue);
		tail.next = tempNode;
		tail = tempNode;
	}// Of enqueue

	/**
	 **********************
	 * Dequeue.
	 *
	 * @return The value at the header
	 **********************
	 */
	public int dequeue() {
		if (header == tail) {// 队列为空
			System.out.println("No element in the queue");
			return -1;
		} // Of if

		int resultValue = header.next.data;

		header.next = header.next.next;

		// The queue becomes empty(出队列后，若队列为空，则需要修改队尾指针）
		if (header.next == null) {
			tail = header;
		} // Of if

		return resultValue;
	}// Of dequeue

	/**
	 **********************
	 * Overrides the method claimed in Object, the superclass of any class.
	 **********************
	 */
	public String toString() {
		String resultString = "";

		if (header.next == null) {
			return "empty";
		} // Of if

		Node tempNode = header.next;
		while (tempNode != null) {
			resultString += tempNode.data + ",";
			tempNode = tempNode.next;
		} // Of while

		return resultString;
	}// Of toString

	/**
	 **********************
	 * The entrance of the program.
	 *
	 * @param args Not used now
	 **********************
	 */
	public static void main(String args[]) {
		LinkedQueue tempQueue = new LinkedQueue();
		System.out.println("Initialized, the list is: " + tempQueue.toString());

		for (int i = 0; i < 5; i++) {
			tempQueue.enqueue(i + 1);
		} // Of for i
		System.out.println("Enqueue, the queue is: " + tempQueue.toString());

		tempQueue.dequeue();
		System.out.println("Dequeue, the queue is: " + tempQueue.toString());

		int tempValue;
		for (int i = 0; i < 5; i++) {
			tempValue = tempQueue.dequeue();
			System.out.println("Looped delete " + tempValue + ", the new queue is: " + tempQueue.toString());
		} // Of for i

		for (int i = 0; i < 3; i++) {
			tempQueue.enqueue(i + 10);
		} // Of for i
		System.out.println("Enqueue, the queue is: " + tempQueue.toString());
	}// Of main
}// Of class LinkedQueue

2.运行结果：