Count_Leaf_Nodes.java

public class Count_Leaf_Nodes {
    package org.arpit.java2blog.binarytree;

    public class BinaryTreeLeafCount {

        public static class TreeNode
        {
            int data;
            TreeNode left;
            TreeNode right;
            TreeNode(int data)
            {
                this.data=data;
            }
        }

        // Recursive Solution
        /* To get the count of leaf nodes in a binary tree*/
        public static  int getLeafCountOfBinaryTree(TreeNode node)
        {
            if(node == null)
                return 0;
            if(node.left ==null && node.right==null)
                return 1;
            else
                return getLeafCountOfBinaryTree(node.left)+ getLeafCountOfBinaryTree(node.right);
        }

        public static void main(String[] args)
        {
            // Creating a binary tree
            TreeNode rootNode=createBinaryTree();
            System.out.println("Number of leaf nodes in binary tree :"+getLeafCountOfBinaryTree(rootNode));
        }

        public static TreeNode createBinaryTree()
        {

            TreeNode rootNode =new TreeNode(40);
            TreeNode node20=new TreeNode(20);
            TreeNode node10=new TreeNode(10);
            TreeNode node30=new TreeNode(30);
            TreeNode node60=new TreeNode(60);
            TreeNode node50=new TreeNode(50);
            TreeNode node70=new TreeNode(70);

            rootNode.left=node20;
            rootNode.right=node60;

            node20.left=node10;
            node20.right=node30;

            node60.left=node50;
            node60.right=node70;

            return rootNode;
        }
    }
}