binary tree

1# Python program to for tree traversals 
2
3# A class that represents an individual node in a 
4# Binary Tree 
5class Node: 
6	def __init__(self,key): 
7		self.left = None
8		self.right = None
9		self.val = key 
10
11
12# A function to do inorder tree traversal 
13def printInorder(root): 
14
15	if root: 
16
17		# First recur on left child 
18		printInorder(root.left) 
19
20		# then print the data of node 
21		print(root.val), 
22
23		# now recur on right child 
24		printInorder(root.right) 
25
26
27
28# A function to do postorder tree traversal 
29def printPostorder(root): 
30
31	if root: 
32
33		# First recur on left child 
34		printPostorder(root.left) 
35
36		# the recur on right child 
37		printPostorder(root.right) 
38
39		# now print the data of node 
40		print(root.val), 
41
42
43# A function to do preorder tree traversal 
44def printPreorder(root): 
45
46	if root: 
47
48		# First print the data of node 
49		print(root.val), 
50
51		# Then recur on left child 
52		printPreorder(root.left) 
53
54		# Finally recur on right child 
55		printPreorder(root.right) 
56
57
58# Driver code 
59root = Node(1) 
60root.left	 = Node(2) 
61root.right	 = Node(3) 
62root.left.left = Node(4) 
63root.left.right = Node(5) 
64print "Preorder traversal of binary tree is"
65printPreorder(root) 
66
67print "\nInorder traversal of binary tree is"
68printInorder(root) 
69
70print "\nPostorder traversal of binary tree is"
71printPostorder(root) 
72

1class Node:
2    def __init__(self,key):
3        self.left = None
4        self.right = None
5        self.val = key
6 
7root = Node(1)
8root.left      = Node(2);
9root.right     = Node(3);
10root.left.left  = Node(4);
11