Write a recursive function to count the number of leaf nodes in the binary tree pointed at by "root". You must use the "isLeaf" method to check if the node is leaf or not. That is, do not check the value of the left and right children to see if they are null or not to decide if the node is a leaf.
int BTleaf(BinNode root) { // Your code goes between these lines // Your code goes between these lines }