added missing code to chapter 5

Author: loiane

chapter05/05-CircularLinkedList.js

@@ -0,0 +1,187 @@
+function CircularLinkedList() {
+
+    var Node = function(element){
+
+        this.element = element;
+        this.next = null;
+    };
+
+    var length = 0;
+    var head = null;
+
+    this.append = function(element){
+
+        var node = new Node(element),
+            current;
+
+        if (head === null){ //first node on list
+            head = node;
+        } else {
+
+            current = head;
+
+            //loop the list until find last item
+            while(current.next !== head){ //last element will be head instead of NULL
+                current = current.next;
+            }
+
+            //get last item and assign next to added item to make the link
+            current.next = node;
+        }
+
+        //set node.next to head - to have circular list
+        node.next = head;
+
+        length++; //update size of list
+    };
+
+    this.insert = function(position, element){
+
+        //check for out-of-bounds values
+        if (position >= 0 && position <= length){
+
+            var node = new Node(element),
+                current = head,
+                previous,
+                index = 0;
+
+            if (position === 0){ //add on first position
+
+                node.next = current;
+
+                //update last element
+                while(current.next !== head){ //last element will be head instead of NULL
+                    current = current.next;
+                }
+
+                head = node;
+                current.next = head;
+
+            } else {
+                while (index++ < position){
+                    previous = current;
+                    current = current.next;
+                }
+                node.next = current;
+                previous.next = node;
+
+                if (node.next === null){ //update in case last element
+                    node.next = head;
+                }
+            }
+
+            length++; //update size of list
+
+            return true;
+
+        } else {
+            return false;
+        }
+    };
+
+    this.removeAt = function(position){
+
+        //check for out-of-bounds values
+        if (position > -1 && position < length){
+
+            var current = head,
+                previous,
+                index = 0;
+
+            //removing first item
+            if (position === 0){
+
+                while(current.next !== head){ //needs to update last element first
+                    current = current.next;
+                }
+
+                head = head.next;
+                current.next = head;
+
+            } else { //no need to update last element for circular list
+
+                while (index++ < position){
+
+                    previous = current;
+                    current = current.next;
+                }
+
+                //link previous with current's next - skip it to remove
+                previous.next = current.next;
+            }
+
+            length--;
+
+            return current.element;
+
+        } else {
+            return null;
+        }
+    };
+
+    this.remove = function(element){
+
+        var index = this.indexOf(element);
+        return this.removeAt(index);
+    };
+
+    this.indexOf = function(element){
+
+        var current = head,
+            index = -1;
+
+        //check first item
+        if (element == current.element){
+            return 0;
+        }
+
+        index++;
+
+        //check in the middle of the list
+        while(current.next !== head){
+
+            if (element == current.element){
+                return index;
+            }
+
+            current = current.next;
+            index++;
+        }
+
+        //check last item
+        if (element == current.element){
+            return index;
+        }
+
+        return -1;
+    };
+
+    this.isEmpty = function() {
+        return length === 0;
+    };
+
+    this.size = function() {
+        return length;
+    };
+
+    this.getHead = function(){
+        return head;
+    };
+
+    this.toString = function(){
+
+        var current = head,
+            s = current.element;
+
+        while(current.next !== head){
+            current = current.next;
+            s += ', ' + current.element;
+        }
+
+        return s.toString();
+    };
+
+    this.print = function(){
+        console.log(this.toString());
+    };
+}

chapter05/06-CircularDoublyLinkedList.js

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+<script type="text/javascript" src="05-CircularLinkedList.js"></script>
+<script type="text/javascript" src="06-UsingCircularLinkedList.js"></script>
+</body>
+</html>

chapter05/06-UsingCircularLinkedList.html

@@ -0,0 +1,28 @@
+var circularLinkedList = new CircularLinkedList();
+
+circularLinkedList.append(15);
+circularLinkedList.print();
+
+circularLinkedList.append(16);
+circularLinkedList.print();
+
+circularLinkedList.insert(0,14);
+circularLinkedList.print();
+
+circularLinkedList.insert(1,14.5);
+circularLinkedList.print();
+
+circularLinkedList.insert(4,17);
+circularLinkedList.print();
+
+circularLinkedList.removeAt(0);
+circularLinkedList.print();
+
+circularLinkedList.removeAt(1);
+circularLinkedList.print();
+
+circularLinkedList.removeAt(2);
+circularLinkedList.print();
+
+console.log(circularLinkedList.indexOf(14.5));
+console.log(circularLinkedList.indexOf(16));