boundary traversal cpp

// program to print the boundary traversal of a binary tree

#include <iostream>
#include <queue>
#include <map>

using namespace std;

// node class
class node{
public:
    int data;
    node* left;
    node* right;
};

// function that returns a pointer to new node
node* createNode(int element){
    node* temp = (node*) malloc(sizeof(node));
    temp->data = element;
    temp->left = NULL;
    temp->right = NULL;
    return temp;
}

// function to print the left boundary of the tree
void print_left_boundary(node* root){
    if (root != NULL){
        if (root->left != NULL){
            cout<<root->data<<" ";
            print_left_boundary(root->left);
        }else if (root->right != NULL){
            cout<<root->data<<" ";
            print_left_boundary(root->right);
        }
    }
    return;
}

// function to print the right boundary of the tree
void print_right_boundary(node* root){
    if (root != NULL){
        if (root->right != NULL){
            print_right_boundary(root->right);
            cout<<root->data<<" ";
        }else if (root->left != NULL){
            print_right_boundary(root->left);
            cout<<root->data<<" ";
        }
    }
    return;
}

// function to print the leaves of a binary tree
void print_leaves(node* root){
    if (root != NULL){
        print_leaves(root->left);
        if(root->left == NULL && root->right == NULL){
            cout<<root->data<<" ";
        }
        print_leaves(root->right);
    }
}

void boundary_traversal(node* root){
    print_left_boundary(root);
    print_leaves(root);
    print_right_boundary(root);
    return;
}


int main() {
    node* head = createNode(1);
    head->left = createNode(2);
    head->right = createNode(3);
    head->left->left = createNode(4);
    head->left->right = createNode(5);
    head->right->right = createNode(6);
    head->left->left->right = createNode(7);
    head->right->right->left = createNode(8);
    head->left->left->right->left = createNode(9);
    head->left->left->right->left->left = createNode(10);
    head->right->right->left->right = createNode(11);

    cout<<"Boundary traversal of the binary tree is : "<<endl;
    boundary_traversal(head);
    return 0;
}


/*

Boundary traversal of the binary tree is :
1 2 4 7 9 10 5 11 8 6 3 1
Process finished with exit code 0

*/