Tree_Preorder_Traversal.js added

Tree_Preorder_Traversal/Tree_Preorder_Traversal.js.js

@@ -0,0 +1,93 @@
+//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
+*/