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)