Data Structure Binary Tree: Inorder Tree Traversal without recursion and without stack!

http://www.geeksforgeeks.org/inorder-tree-traversal-without-recursion-and-without-stack/

 #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) { }
 };

 void print(node *root) {
     if (!root) return;
     node *cur = root;
     while (cur) {
         if (!cur->left) {
             cout << cur->data << " ";
             cur = cur->right;
         }
         else {
             node *pre = cur->left;
             while (pre->right && pre->right != cur) pre = pre->right;
             if (pre->right == NULL) {
                 pre->right = cur;
                 cur = cur->left;
             }
             else {
                 pre->right = NULL;
                 cout << cur->data << " ";
                 cur = cur->right;
             }
         }
     }
 }

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