Inorder, pre-order and post-order Traversal

preOrder

/** approach
 a b c root left right
**/
class Node {
	constructor(value, left, right) {
		this.value = value;
		this.left = left || null;
		this.right = right || null;
	}
}
 
function inOrder(node) {
 
	if (node != null) {
		inOrder(node.left);
		console.log(node.value);
		inOrder(node.right);
	}
}
 
function preOrder(node) {
 
	if (node != null) {
		console.log(node.value);
		preOrder(node.left);
		preOrder(node.right);
	}
}
 
function postOrder(node) {
 
	if (node != null) {
		//b c a left right root
		postOrder(node.left);
		postOrder(node.right);
		console.log(node.data);
	}
}
 
const root = new Node(5, null, null);
const twoVal = new Node(2);
const sixVal = new Node(6);
root.left = twoVal;
root.right = sixVal;
 
inOrder(root);

inOrder in Java

class Node {
    int data;
    Node left;
    Node right;
}
 
    public static void inOrder(Node root) {
        if(root != null) {
            inOrder(root.left);
            System.out.print(root.data+" ");
            inOrder(root.right);
        }
    }

class Node {
	constructor(value, left, right) {
		this.value = value;
		this.left = left || null;
		this.right = right || null;
	}
}
 
function inOrder(node) {
 
	if (node != null) {
		inOrder(node.left);
		console.log(node.value);
		inOrder(node.right);
	}
}
 
const root = new Node(5, null, null);
const twoVal = new Node(2);
const sixVal = new Node(6);
root.left = twoVal;
root.right = sixVal;
 
inOrder(root);
 
/** Output
2
5
6
**/