 ### Python program to count the number of nodes in Binary Search Tree.

Description:
This program is to count the number of nodes in Binary Search Tree.
Algo: -
1. Make a class for node in a tree.
2. Form the tree by creating nodes.
3. Traverse the tree.
4. During traversal count the nodes one by one.
5. Display the no. of nodes.
Program:
`#A class that represents the individual node of the Binary treeclass Node:    def __init__(self, key):        self.left = None        self.right = None        self.val = key#A function to count no. of nodes.def counter(root,count):    if root:        #First recur the left child        if root.left:            count=counter(root.left,count)        count+=1        #Recur the right child at last        if root.right:            count=counter(root.right,count)        return countdef main():    root = Node(1)    root.left = Node(2)    root.right = Node(3)    root.left.left = Node(4)    root.left.right = Node(5)    root.left.right.left = Node(6)    root.left.right.right = Node(7)    count=0    count=counter(root,count)    print('The no. of nodes in the tree are = ',count)#Driver codeif __name__ == "__main__":    main()`
Output:
The no. of nodes in the tree are = 7 #### More Articles of Shivam Kalra:

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