Tree Traversals (Inorder, Preorder and Postorder)

# Python program to for tree traversals

# A class that represents an individual node in a
# Binary Tree


class Node:
	def __init__(self, key):
		self.left = None
		self.right = None
		self.val = key


# A function to do inorder tree traversal
def printInorder(root):

	if root:

		# First recur on left child
		printInorder(root.left)

		# then print the data of node
		print(root.val),

		# now recur on right child
		printInorder(root.right)


# A function to do postorder tree traversal
def printPostorder(root):

	if root:

		# First recur on left child
		printPostorder(root.left)

		# the recur on right child
		printPostorder(root.right)

		# now print the data of node
		print(root.val),


# A function to do preorder tree traversal
def printPreorder(root):

	if root:

		# First print the data of node
		print(root.val),

		# Then recur on left child
		printPreorder(root.left)

		# Finally recur on right child
		printPreorder(root.right)


# Driver code
root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)
print "Preorder traversal of binary tree is"
printPreorder(root)

print "\nInorder traversal of binary tree is"
printInorder(root)

print "\nPostorder traversal of binary tree is"
printPostorder(root)

// javascript program for different tree traversals

/* Class containing left and right child of current
node and key value*/
class Node {
	constructor(val) {
		this.key = val;
		this.left = null;
		this.right = null;
	}
}

	// Root of Binary Tree
	var root = null;

	
	/*
	* Given a binary tree, print its nodes according to the "bottom-up" postorder
	* traversal.
	*/
	function printPostorder(node) {
		if (node == null)
			return;

		// first recur on left subtree
		printPostorder(node.left);

		// then recur on right subtree
		printPostorder(node.right);

		// now deal with the node
		document.write(node.key + " ");
	}

	/* Given a binary tree, print its nodes in inorder */
	function printInorder(node) {
		if (node == null)
			return;

		/* first recur on left child */
		printInorder(node.left);

		/* then print the data of node */
		document.write(node.key + " ");

		/* now recur on right child */
		printInorder(node.right);
	}

	/* Given a binary tree, print its nodes in preorder */
	function printPreorder(node) {
		if (node == null)
			return;

		/* first print data of node */
		document.write(node.key + " ");

		/* then recur on left sutree */
		printPreorder(node.left);

		/* now recur on right subtree */
		printPreorder(node.right);
		
	}



	// Driver method
	
	
		root = new Node(1);
		root.left = new Node(2);
		root.right = new Node(3);
		root.left.left = new Node(4);
		root.left.right = new Node(5);

		document.write("Preorder traversal of binary tree is <br/>");
		printPreorder(root);

		document.write("<br/>Inorder traversal of binary tree is <br/>");
		printInorder(root);

		document.write("<br/>Postorder traversal of binary tree is <br/>");
		printPostorder(root);

// This code is contributed by aashish1995