使用JavaScript实现单向链表

一、实现功能

　　1、链表元素头部插入 this.unShift = function(data) {}

　　2、链表元素尾部插入 this.append= function(data) {} //返回boolean

　　3、链表元素按位置插入 this.insert= function(position, data) {} //返回boolean

　　4、链表元素头部删除 this.shift= function() {} //返回boolean

　　5、链表元素尾部删除 this.pop = function() {}　//返回boolean

　　6、链表按元素删除 this.removeData = function(data) {} //返回boolean

　　7、链表按下标删除 this.removePos = function(position) {} //返回boolean

　　8、链表是否为空 this.isEmpty= function() {} //返回boolean

　　9、链表元素组成的字符串 this.toString= function() {} //返回 string

　　10、链表的长度 this.length= function() {} //返回number

　　11、链表查找元素 this.searchData= function(data) {}  //返回obj={index:,data:}

二、节点声明

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function Node(data) {     this.data = data  //数据     this.next = null  //指向 }

三、完整功能代码

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function List() {     let length = 0     let head = null     this.append = (data) => { // 向链表末尾添加元素         let node = new Node(data)         let current         if(head === null) {             head = node         }         else {             current = head             while(current.next) {                 current = current.next             }             current.next = node         }         length ++         return true     }     this.insert = (position, data) => { // 向链表指定位置添加元素         if (position >= 0 && position <= length) { //检查是否越界             let node = new Node(data),                 current = head,                 previous,                 index = 0             if (position === 0) { //在第一个位置添加                 node.next = current                 head = node             }else {                 while (index ++ < position) {                     previous = current                     current = current.next                 }                 //通过改变指针，将node链接在previous和current之间                 node.next = current                 previous.next = node             }             length ++             return true         }else {             return false         }     }     this.removeData = (data) => { // 通过数据删除链表元素         let previous,             current,             index = 0         if (head === null) {             return false         }         current = head         while(index ++ < length && current.data !== data) {             previous = current             current = current.next         }         if(index > length) {             return false         }else {             current.next = current.next             length --             return true         }     }     this.removePos = (position) => { // 通过位置删除链表元素         if( position >= -1 && position < length) {             let previous,                 current = head,                 index = 0             if (position === 0) {                 head = current.next             }else {                 while(index ++ < position) {                     previous = current                     current = current.next                 }                 previous.next = current.next             }             length --             return true         }else {             return false         }     }     this.unShift = (data) => {  //向链表首插入元素         let node = new Node(data),             current = head         node.next = current         head = node         length ++         return true     }     this.shift = () => {  //删除链表首元素         let current = head         if(head === null) {             return false         }         else {             head = current.next             length --             return true         }     }     this.pop = () => { // 删除链表尾元素         let current,             previous         if (head === null){             return false         }         current = head         while(current) {             previous = current             current = current.next         }         previous = null         length --         return true     }     this.isEmpty = () => {         return length === 0     }     this.length = () => {         return length     }     this.searchData = (data) => { //查找元素         let current,             index = 0,             obj = {}         if( head === null ) {             return false         }         current = head         while(index ++ < length && current.data !== data) {             current = current.next         }         obj = {             index: index,             data: current.data         }         return obj     }     this.toString = () => { //输出数据组成的字符串         let resultStr = "",             current,             index = length         if (head === null) {             return ""         }         current = head         while(index -- > 0) {             resultStr += "," + current.data             current = current.next         }         return resultStr.slice(1)     } }

四、测试代码及结果

　　1、测试代码

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<!DOCTYPE html> <html> <head>     <title>test</title>     <script type="text/javascript" src="./singleList.js"></script> </head> <body>     <script type="text/javascript">         let singleList = new List()         console.log(singleList.append("1"))         console.log(singleList.toString())         console.log(singleList.append("2"))         console.log(singleList.toString())         console.log(singleList.append("3"))         console.log(singleList.toString())         console.log(singleList.unShift(0))         console.log(singleList.toString())         console.log(singleList.insert(2,"4"))         console.log(singleList.toString())         console.log(singleList.shift())         console.log(singleList.toString())         console.log(singleList.pop())         console.log(singleList.toString())         console.log(singleList.searchData("1"))         console.log(singleList.removePos(1))         console.log(singleList.toString())         console.log(singleList.removeData("1"))         console.log(singleList.toString())         console.log(singleList.isEmpty())     </script> </body> </html>

　　2、测试结果