Program to find count of nodes having 2 children

// C++ program to find number of full nodes
// at a given level
#include <bits/stdc++.h>
using namespace std;

// A binary tree node
struct Node {
	int data;
	struct Node *left, *right;
};

// Utility function to allocate memory for a new node
struct Node* newNode(int data)
{
	struct Node* node = new (struct Node);
	node->data = data;
	node->left = node->right = NULL;
	return (node);
}

// Function that returns the height of binary tree
int height(struct Node* root)
{
	if (root == NULL)
		return 0;

	int lheight = height(root->left);
	int rheight = height(root->right);

	return max(lheight, rheight) + 1;
}

// Level Order traversal to find the number of nodes
// having two children
void LevelOrder(struct Node* root, int level, int& count)
{
	if (root == NULL)
		return;

	if (level == 1 && root->left && root->right)
		count++;

	else if (level > 1) {
		LevelOrder(root->left, level - 1, count);
		LevelOrder(root->right, level - 1, count);
	}
}

// Returns the number of full nodes
// at a given level
int CountFullNodes(struct Node* root, int L)
{
	// Stores height of tree
	int h = height(root);

	// Stores count of nodes at a given level
	// that have two children
	int count = 0;

	LevelOrder(root, L, count);

	return count;
}

// Driver code
int main()
{
	struct Node* root = newNode(7);
	root->left = newNode(5);
	root->right = newNode(6);
	root->left->left = newNode(8);
	root->left->right = newNode(1);
	root->left->left->left = newNode(2);
	root->left->left->right = newNode(11);
	root->right->left = newNode(3);
	root->right->right = newNode(9);
	root->right->right->right = newNode(13);
	root->right->right->left = newNode(10);
	root->right->right->right->left = newNode(4);
	root->right->right->right->right = newNode(12);

	int L = 3;

	cout << CountFullNodes(root, L);

	return 0;
}