Java单链表基本操作的实现

package com.tyxh.link; 
//节点类 
public 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 + " "); 
} 
} 
package com.tyxh.link; 
//单链表 
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; 
} 
} 
package com.tyxh.link; 
//测试类 
public class TestLinkList { 
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); 
} 
}