Java实现单链表基本操作

public class Node {
public int value;
public Node next;

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

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

}

public class LinkedList {

public Node first;// 定义头结点
public int pos = 0;// 节点的位置

/**
* 构造方法
*/
public LinkedList() {
this.first = null;
}

/**
* 插入头结点(头插法)
*
* @param data
*/
public void addFirstNode(int data) {
Node node = new Node(data);
node.next = first;
first = node;
}

/**
* 删除头结点
*
* @return
*/
public Node deleteFirstNode() {

Node tempNode = first;
first = tempNode.next;
return tempNode;
}

/**
* 在指定位置添加元素
*
* @param index
* @param data
*/
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;
}

/**
* 在指定位置删除元素
*
* @param index
* @return
*/
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;

}

/**
* 根据数据删除元素
*
* @param data
* @return
*/
public Node deleteByData(int data) {
Node current = first;
Node previous = first;
while (current.value != 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;
}

/**
* 显示所有元素
*/
public void displayAllNode() {
Node current = first;
while (current != null) {
current.display();
current = current.next;
}
System.out.println();
}

/**
* 根据位置查找元素
*
* @param index
* @return
*/
public Node findByPos(int index) {
Node current = first;
while (pos != index) {
current = current.next;
pos++;
}
pos = 0;
return current;
}

/**
* 根据数值查找元素
*
* @param data
* @return
*/
public Node findByData(int data) {
Node current = first;
while (current.value != data) {
if (current.next == null) {
return null;
}
current = current.next;
}
return current;
}

public static void main(String[] args) {
LinkedList linkedList = new LinkedList();
// 添加元素
linkedList.addFirstNode(26);
linkedList.addFirstNode(25);
linkedList.addFirstNode(23);
linkedList.addFirstNode(22);
linkedList.addFirstNode(20);
linkedList.displayAllNode();// 此时显示内容为 ：20 22 23 25 26

linkedList.add(1, 21);
linkedList.add(4, 24);
linkedList.displayAllNode();// 此时显示内容为 ：20 21 22 23 24 25 26

Node node = linkedList.deleteByPos(0);
System.out.println("删除元素为：" + node.value);
linkedList.displayAllNode();

Node node2 = linkedList.deleteByData(21);
System.out.println("删除元素为：" + node2.value);
linkedList.displayAllNode();

Node node3 = linkedList.deleteFirstNode();
System.out.println("删除元素为：" + node3.value);
linkedList.displayAllNode();

Node node4 = linkedList.findByPos(0);
System.out.println("查找到的元素为:" + node4.value);
linkedList.displayAllNode();

Node node5 = linkedList.findByData(24);
System.out.println("查找到的元素为:" + node5.value);
linkedList.displayAllNode();

}

}