Data Structure Binary Tree: Boundary Traversal of binary tree

http://www.geeksforgeeks.org/boundary-traversal-of-binary-tree/
 1 #include <iostream>
 2 #include <vector>
 3 #include <algorithm>
 4 #include <queue>
 5 #include <stack>
 6 #include <string>
 7 #include <fstream>
 8 #include <map>
 9 using namespace std;
10 
11 struct node {
12     int data;
13     struct node *left, *right;
14     node() : data(0), left(NULL), right(NULL) { }
15     node(int d) : data(d), left(NULL), right(NULL) { }
16 };
17 
18 void printleft(node *root) {
19     if (!root) return;
20     if (root->left) {
21         cout << root->data << " ";
22         printleft(root->left);
23     }
24     else if (root->right) {
25         cout << root->data << " ";
26         printleft(root->right);
27     }
28 }
29 
30 void printleaf(node *root) {
31     if (!root) return;
32     printleaf(root->left);
33     if (!root->left && !root->right) cout << root->data << " ";
34     printleaf(root->right);
35 }
36 
37 void printright(node *root) {
38     if (!root) return;
39     if (root->right) {
40         printright(root->right);
41         cout << root->data << " ";
42     }
43     else if (root->left) {
44         printright(root->left);
45         cout << root->data << " ";
46     }
47 }
48 
49 void printboundary(node *root) {
50     if (!root) return;
51     cout << root->data << " ";
52     printleft(root->left);
53     printleaf(root);
54     printright(root->right);
55 }
56 
57 int main() {
58     node *root = new node(20);
59     root->left = new node(8);
60     root->right = new node(22);
61     root->left->left = new node(4);
62     root->left->right = new node(12);
63     root->right->right = new node(25);
64     root->left->right->left = new node(10);
65     root->left->right->right = new node(14);
66     printboundary(root);
67     return 0;
68 }