Data Structure Binary Tree: Check if a given Binary Tree is SumTree

http://www.geeksforgeeks.org/check-if-a-given-binary-tree-is-sumtree/

 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <queue>
 #include <stack>
 #include <string>
 #include <fstream>
 using namespace std;

 struct node {
     int data;
     struct node *left, *right;
     node() : data(), left(NULL), right(NULL) { }
     node(int d) : data(d), left(NULL), right(NULL) { }
 };

 bool isleaf(node *root) {
     return !root->left && !root->right;
 }

 bool issumtree(node *root) {
     if (!root || isleaf(root)) return true;
     int l = ;
     int r = ;
     if (root->left == NULL) l = ;
     else if (isleaf(root->left)) l = root->left->data;
     else l =  * root->left->data;
     if (root->right == NULL) r = ;
     else if (isleaf(root->right)) r = root->right->data;
     else r =  * root->right->data;
     return root->data == l + r && issumtree(root->left) && issumtree(root->right);
 }

 int main() {
     node *root = new node();
     root->left = new node();
     root->right = new node();
     root->left->left = new node();
     root->left->right = new node();
     root->right->right = new node();
     if (issumtree(root)) cout << "yes" << endl;
     else cout << "NO" << endl;
     return ;
 }