Merge pull request #49 from christianbender/changed_linklist

wrote more object oriented

Data Structures/Linked List/singlylinklist.js

@@ -8,63 +8,72 @@
 
 //Functions - add, remove, indexOf, elementAt, addAt, removeAt, view
 
+// class LinkedList and constructor
 //Creates a LinkedList
-function LinkedList(){
+var LinkedList = (function () {
-  //Length of linklist and head is null at start
-  var length = 0;
-  var head = null;
 
+  function LinkedList() {
+    //Length of linklist and head is null at start
+    this.length = 0;
+    this.head = null;
+
+  }
+
+  // class node (constructor)
   //Creating Node with element's value
-  var Node = function(element){
+  var Node = (function () {
-    this.element = element;
+    function Node(element) {
-    this.next = null;
+      this.element = element;
-  };
+      this.next = null;
+    }
+    return Node;
+  }());
 
   //Returns length
-  this.size = function(){
+  LinkedList.prototype.size = function () {
-    return length;
+    return this.length;
   };
 
   //Returns the head
-  this.head = function(){
+  LinkedList.prototype.head = function () {
-    return head;
+    return this.head;
   };
 
   //Creates a node and adds it to linklist
-  this.add = function(element){
+  LinkedList.prototype.add = function (element) {
     var node = new Node(element);
     //Check if its the first element
-    if(head === null){
+    if (this.head === null) {
-      head = node;
+      this.head = node;
     }
     else {
-      var currentNode = head;
+      var currentNode = this.head;
 
       //Loop till there is node present in the list
-      while(currentNode.next){
+      while (currentNode.next) {
-          currentNode = currentNode.next;
+        currentNode = currentNode.next;
       }
 
       //Adding node to the end of the list
       currentNode.next = node;
     }
     //Increment the length
-    length++;
+    this.length++;
   };
 
   //Removes the node with the value as param
-  this.remove = function(element){
+  LinkedList.prototype.remove = function (element) {
-    var currentNode = head;
+    var currentNode = this.head;
     var previousNode;
 
     //Check if the head node is the element to remove
-    if(currentNode.element === element){
+    if (currentNode.element === element) {
-      head = currentNode.next;
+      this.head = currentNode.next;
     }
     else {
 
       //Check which node is the node to remove
-      while(currentNode.element !== element) {
+      while (currentNode.element !== element) {
         previousNode = currentNode;
         currentNode = currentNode.next;
       }
@@ -74,25 +83,25 @@ function LinkedList(){
     }
 
     //Decrementing the length
-    length--;
+    this.length--;
   };
 
   //Return if the list is empty
-  this.isEmpty = function(){
+  LinkedList.prototype.isEmpty = function () {
-    return length === 0;
+    return this.length === 0;
   };
 
   //Returns the index of the element passed as param otherwise -1
-  this.indexOf = function(element) {
+  LinkedList.prototype.indexOf = function (element) {
-    var currentNode = head;
+    var currentNode = this.head;
     var index = -1;
 
-    while(currentNode){
+    while (currentNode) {
       index++;
 
       //Checking if the node is the element we are searching for
-      if(currentNode.element === element){
+      if (currentNode.element === element) {
-        return index+1;
+        return index + 1;
       }
       currentNode = currentNode.next;
     }
@@ -101,10 +110,10 @@ function LinkedList(){
   };
 
   //Returns the element at an index
-  this.elementAt = function(index){
+  LinkedList.prototype.elementAt = function (index) {
-    var currentNode = head;
+    var currentNode = this.head;
     var count = 0;
-    while(count < index){
+    while (count < index) {
       count++;
       currentNode = currentNode.next;
     }
@@ -112,23 +121,23 @@ function LinkedList(){
   };
 
   //Adds the element at specified index
-  this.addAt = function(index, element){
+  LinkedList.prototype.addAt = function (index, element) {
     index--;
     var node = new Node(element);
 
-    var currentNode = head;
+    var currentNode = this.head;
     var previousNode;
     var currentIndex = 0;
 
     //Check if index is out of bounds of list
-    if(index > length){
+    if (index > this.length) {
       return false;
     }
 
     //Check if index is the start of list
-    if(index === 0){
+    if (index === 0) {
       node.next = currentNode;
-      head = node;
+      this.head = node;
     }
     else {
       while (currentIndex < index) {
@@ -143,24 +152,25 @@ function LinkedList(){
     }
 
     //Incrementing the length
-    length++;
+    this.length++;
+    return true;
   };
 
   //Removes the node at specified index
-  this.removeAt = function(index) {
+  LinkedList.prototype.removeAt = function (index) {
     index--;
-    var currentNode = head;
+    var currentNode = this.head;
     var previousNode;
     var currentIndex = 0;
 
     //Check if index is present in list
-    if(index < 0 || index >= length){
+    if (index < 0 || index >= this.length) {
       return null;
     }
 
     //Check if element is the first element
     if (index === 0) {
-      head = currentNode.next;
+      this.head = currentNode.next;
     }
     else {
       while (currentIndex < index) {
@@ -172,21 +182,25 @@ function LinkedList(){
     }
 
     //Decrementing the length
-    length--;
+    this.length--;
     return currentNode.element;
   };
 
   //Function to view the LinkedList
-  this.view = function () {
+  LinkedList.prototype.view = function () {
-    var currentNode = head;
+    var currentNode = this.head;
     var count = 0;
-    while(count < length){
+    while (count < this.length) {
       count++;
       console.log(currentNode.element);
       currentNode = currentNode.next;
     }
   };
-};
+
+  // returns the constructor
+  return LinkedList;
+
+}());
 
 //Implementation of LinkedList
 var linklist = new LinkedList();
@@ -197,7 +211,7 @@ linklist.add(12);
 linklist.add(17);
 console.log(linklist.size());
 console.log(linklist.removeAt(4));
-linklist.addAt(4,15);
+linklist.addAt(4, 15);
 console.log(linklist.indexOf(8));
 console.log(linklist.size());
 linklist.view();