Java单链表的实现代码

public class Node {protected Node next; //指针域 public int data;//数据域 public Node( int data) { this. data = data; } //显示此节点 public void display() { System. out.print( data + " "); } }

public 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;}}

public class TestLinkList {public static void main(String[] args) { LinkList linkList = new LinkList(); linkList.addFirstNode(20); linkList.addFirstNode(21); linkList.addFirstNode(19); //print19,21,20 linkList.add(1, 22); //print19,22,21,20 linkList.add(2, 23); //print19,22,23,21,20 linkList.add(3, 99); //print19,22,23,99,21,20 //调用此方法会print 19,22,23,99,21,20 linkList.displayAllNodes(); }}