链表的基本操作java语言实现

package com.baorant;

public class JavaDemo {

    public static void main(String[] args) {
        LinkList linkList = new LinkList();
        linkList.addFirstNode(20);
        linkList.addFirstNode(21);
        linkList.addFirstNode(19);
        // 19,21,20
        linkList.add(1, 22); // 19,22,21,20
        linkList.add(2, 23); // 19,22,23,21,20
        linkList.add(3, 99); // 19,22,23,99,21,20
        linkList.displayAllNodes();
        // Node node = linkList.deleteFirstNode();
        // System.out.println("node : " + node.data);
        // linkList.displayAllNodes();
        // node = linkList.deleteByPos(2);
        // System.out.println("node : " + node.data);
        // linkList.displayAllNodes();
        // linkList.deleteFirstNode();
        Node node = linkList.deleteByData(19);
        // Node node = linkList.deleteByPos(0);
        System.out.println("node : " + node.data);
        linkList.displayAllNodes();
        Node node1 = linkList.findByPos(0);
        System.out.println("node1: " + node1.data);
        Node node2 = linkList.findByData(22);
        System.out.println("node2: " + node2.data);
    }
}

/**
 * 单节点
 * 
 * @author Baorant
 *
 */
class Node {
    protected Node next; // 指针域
    protected int data;// 数据域

    public Node(int data) {
        this.data = data;
    }

    // 显示此节点
    public void display() {
        System.out.print(data + " ");
    }
}

/**
 * 单链表
 * 
 * @author Baorant
 *
 */

class LinkList {
    public Node first; // 定义一个头结点
    private int pos = 0;// 节点的位置

    public LinkList() {
        this.first = null;
    }

    // 插入一个头节点
    public void addFirstNode(int data) {
        Node node = new Node(data);
        node.next = first;
        first = node;
    }

    // 删除一个头结点,并返回头结点
    public Node deleteFirstNode() {
        Node tempNode = first;
        first = tempNode.next;
        return tempNode;
    }

    // 在任意位置插入节点 在index的后面插入
    public void add(int index, int data) {
        Node node = new Node(data);
        Node current = first;
        Node previous = first;
        while (pos != index) {
            previous = current;
            current = current.next;
            pos++;
        }
        node.next = current;
        previous.next = node;
        pos = 0;
    }

    // 删除任意位置的节点
    public Node deleteByPos(int index) {
        Node current = first;
        Node previous = first;
        while (pos != index) {
            pos++;
            previous = current;
            current = current.next;
        }
        if (current == first) {
            first = first.next;
        } else {
            pos = 0;
            previous.next = current.next;
        }
        return current;
    }

    // 根据节点的data删除节点(仅仅删除第一个)
    public Node deleteByData(int data) {
        Node current = first;
        Node previous = first; // 记住上一个节点
        while (current.data != data) {
            if (current.next == null) {
                return null;
            }
            previous = current;
            current = current.next;
        }
        if (current == first) {
            first = first.next;
        } else {
            previous.next = current.next;
        }
        return current;
    }

    // 显示出所有的节点信息
    public void displayAllNodes() {
        Node current = first;
        while (current != null) {
            current.display();
            current = current.next;
        }
        System.out.println();
    }

    // 根据位置查找节点信息
    public Node findByPos(int index) {
        Node current = first;
        if (pos != index) {
            current = current.next;
            pos++;
        }
        return current;
    }

    // 根据数据查找节点信息
    public Node findByData(int data) {
        Node current = first;
        while (current.data != data) {
            if (current.next == null)
                return null;
            current = current.next;
        }
        return current;
    }
}