Data Structure Binary Tree: Print ancestors of a given binary tree node without recursion

http://www.geeksforgeeks.org/print-ancestors-of-a-given-binary-tree-node-without-recursion/

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

struct node {
    int data;
    struct node *left, *right;
    node() : data(0), left(NULL), right(NULL) { }
    node(int d) : data(d), left(NULL), right(NULL) { }
};

void printancestor(node *root, int key) {
    if (!root) return;
    stack<node*> S;
    while (1) {
        while (root && root->data != key) {
            S.push(root);
            root = root->left;
        }
        if (root && root->data == key) break;
        if (S.top()->right == NULL) {
            root = S.top();
            S.pop();
            while (!S.empty() && S.top()->right == root) {
                root = S.top();
                S.pop();
            }
        }
        root = S.empty()? NULL : S.top()->right;
    }
    while (!S.empty()) {
        cout << S.top()->data << " ";
        S.pop();
    }
}

int main() {
    node *root = new node(1);
    root->left = new node(2);
    root->right = new node(3);
    root->left->left = new node(4);
    root->left->right = new node(5);
    root->right->left = new node(6);
    root->right->right = new node(7);
    root->left->left->left = new node(8);
    root->left->right->right = new node(9);
    root->right->right->left = new node(10);
    for (int i = 1; i < 11; i++) {
        printancestor(root, i);
        cout << endl;
    }
    return 0;
}