tree_traversal.py

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

    # A function to do in order 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)