Preorder Traversal Python

PROGRAM FOR PREORDER TREE TRAVERSAL

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)




OUTPUT:

Preorder traversal of binary tree is
1 2 4 5 3 

CREDITS: https://www.geeksforgeeks.org/tree-traversals-inorder-preorder-and-postorder/