Count the number of leaf nodes

 Qn:

Write a function to count the number of leaf nodes in a binary search tree.

Solution:  count = leaf nodes in left subtree + leaf nodes in right subtree

If a node is having left link as NULL and right link as NULL, then it is a leaf node. So if this condition is true, the call should return 1. If the node is NULL, the call should return 0.

• if node is NULL
• return 0
• if node->left==NULL and node->right==NULL
• return 1
• else
• return count(node->left)+count(node->right)