Data Structure Binary Tree: Boundary Traversal of binary tree

http://www.geeksforgeeks.org/boundary-traversal-of-binary-tree/

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

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

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

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

 void printboundary(node *root) {
     if (!root) return;
     cout << root->data << " ";
     printleft(root->left);
     printleaf(root);
     printright(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();
     root->left->right->left = new node();
     root->left->right->right = new node();
     printboundary(root);
     return ;
 }