### Insert Node in Binary Tree

Let's see how to Insert node in Binary Tree in Java and Java Program to add a Node in Binary Tree. For adding a node, start scanning a Binary Tree level by level and wherever we encounter vacant position, place a new Node there.

See below image to get better understanding of position of a new Node to insert.

Given a binary tree, we need to add a Node with value 8 marked in dotted lines below in its correct position.

### Java Program to insert a Node in Binary Tree and not a Binary Search Tree?

package tree; import java.util.LinkedList; import java.util.Queue; public class AddNodeInBinaryTree { private Node rootNode; public static void main(String[] args) { new AddNodeInBinaryTree(); } public AddNodeInBinaryTree(){ addNodeInBinaryTree(rootNode, 1); addNodeInBinaryTree(rootNode, 2); addNodeInBinaryTree(rootNode, 3); addNodeInBinaryTree(rootNode, 4); addNodeInBinaryTree(rootNode, 5); printTreeLevelOrder(rootNode); } //Iterative way of adding new Node in Binary Tree. private void addNodeInBinaryTree(Node rootNode, int data){ if(rootNode==null){ // No Nodes are Present, create one and assign it to rootNode this.rootNode = new Node(data); }else{ //Nodes present, So checking vacant position for adding new Node in sequential fashion //Start scanning all Levels (level by level) of a tree one by one until we found a node whose either left or right node is null. //For each and every node, we need to check whether Left and Right Node exist? //If exist, then that node is not useful for adding new node but we need to store left and right node of that node for later processing //that is why it is stored in Queue for sequential placement. //If not exist, then we found a node, where new node will be placed but not sure on left or right, so check which side is null and place new node there. Queue<Node> q = new LinkedList<Node>(); q.add(rootNode); while(!q.isEmpty()){ Node node = q.poll(); if(node.getLeft()!=null && node.getRight()!=null){ q.add(node.getLeft()); q.add(node.getRight()); }else{ if(node.getLeft()==null){ node.setLeft(new Node(data)); }else{ node.setRight(new Node(data)); } break; } } } } private void printTreeLevelOrder(Node rootNode) { if(rootNode==null) return; Queue<Node> q = new LinkedList<Node>(); q.add(rootNode); while(!q.isEmpty()){ Node node = q.poll(); System.out.print(node.getData() + " "); if(node.getLeft()!=null) q.add(node.getLeft()); if(node.getRight()!=null) q.add(node.getRight()); } } }

**Enjoy !!!!**

**If you find any issue in post or face any error while implementing, Please comment.**

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