Tree_Preorder_Traversal.js Added

Tree_Preorder_Traversal/Tree_Preorder_Traversal.js

@@ -0,0 +1,99 @@
+
+
+//Tree_Preorder_Traversal in javascript
+class Node
+{
+    constructor(data)
+    {
+        this.data = data;
+        this.left = null; //left child of the node
+        this.right = null; //right child of the node
+    }
+}
+
+class BinarySearchTree
+{
+    constructor()
+    {
+        this.root = null;
+    }
+    //data inserting in tree
+
+    insert(data)
+    {
+        let node = new Node(data);
+        if(this.root == null)
+        {
+            this.root = node;
+        }
+        else
+        {
+            this.insertNode(this.root, node);
+        }
+    }
+
+    insertNode(root, newNode)
+    {
+        if(newNode.data < root.data)
+        {
+            if(root.left == null)
+            {
+                root.left = newNode;
+            }
+            else
+            {
+                this.insertNode(root.left, newNode);
+            }
+        }
+        else if(newNode.data > root.data)
+        {
+            if(root.right == null)
+            {
+                root.right = newNode;
+            }
+            else
+            {
+                this.insertNode(root.right, newNode); 
+            }
+        }
+    }
+
+    getRootNode()
+    {
+        return this.root;
+    }
+    //function of preorder traversal
+
+    preorder(root)
+    {
+        if(root != null)
+        {
+            console.log(root.data); // first line - P L R
+            this.preorder(root.left); // second line
+            this.preorder(root.right); // third line
+        }
+    }
+}
+
+var bst = new BinarySearchTree();
+//tree data insertion statically
+bst.insert(3);
+bst.insert(5);
+bst.insert(1);
+bst.insert(6);
+bst.insert(4);
+var root = bst.getRootNode();
+console.log('Preorder Traversal:');
+bst.preorder(root);
+console.log('\n'); 
+
+/*
+output:
+Preorder Traversal:
+3
+1
+5
+4
+6
+
+*/