Data Structure Binary Tree: How to determine if a binary tree is height-balanced?

http://www.geeksforgeeks.org/how-to-determine-if-a-binary-tree-is-balanced/

 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <queue>
 #include <stack>
 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) { }
 };

 void print(node *node) {
     if (!node) return;
     print(node->left);
     cout << node->data << " ";
     print(node->right);
 }

 bool balanced(node *root, int &height) {
     if (!root) return true;
     int l = ;
     int r = ;
     if (!balanced(root->left, l) || !balanced(root->right, r)) return false;
     if (l - r >=  || r - l >= ) return false;
     height = max(l, r) + ;
     return true;
 }

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