mirror iter bt cpp

// http://code2begin.blogspot.com
// program to mirror a binary tree iteratively
#include <iostream>

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 convert tree into mirror tree iteratively
void mirror_tree(node* root){
    // if the node is null then return
    if (root == NULL){
        return;
    }

    // creating a stack to keep the child pointers
    stack<node *> STACK;

    // push root node on the stack
    STACK.push(root);

    while (!STACK.empty()){

        // remove the top node from the stack
        node *current = STACK.top();
        STACK.pop();

        // swap the left and right nodes
        node* temp = current->left;
        current->left = current->right;
        current->right = temp;

        // as it is a stack, we push right child node first because we want to access it after operating on the left child
        if (current->right != NULL){
            STACK.push(current->right);
        }
        if (current->left != NULL){
            STACK.push(current->left);
        }
    }
}


int main() {

    node* m1 = createNode(8);
    m1->left = createNode(3);
    m1->right = createNode(10);
    m1->left->left = createNode(1);
    m1->left->right = createNode(6);
    m1->left->right->left = createNode(4);
    m1->left->right->right = createNode(7);
    m1->right->right = createNode(14);
    m1->right->right->left = createNode(13);

    node* m2 = createNode(8);
    m2->right = createNode(3);
    m2->left = createNode(10);
    m2->left->left = createNode(14);
    m2->right->left = createNode(6);
    m2->right->right = createNode(1);
    m2->left->left->right = createNode(13);
    m2->right->left->left = createNode(7);
    m2->right->left->right = createNode(4);

    cout<<"Tree #1 before mirroring : ";
    preorder(m1);
    cout<<endl;
    cout<<"Tree #1 after mirroring : ";
    mirror_tree(m1);
    preorder(m1);
    cout<<endl;
    cout<<"\n\nTree #2 is mirror of Tree #1 to check the correctness : "<<endl;
    cout<<"TREE #1 : ";
    preorder(m1);
    cout<<endl;
    cout<<"TREE #2 : ";
    preorder(m2);
    cout<<endl;

}



/*

Tree #1 before mirroring : 8 3 1 6 4 7 10 14 13
Tree #1 after mirroring : 8 10 14 13 3 6 7 4 1


Tree #2 is mirror of Tree #1 to check the correctness :
TREE #1 : 8 10 14 13 3 6 7 4 1
TREE #2 : 8 10 14 13 3 6 7 4 1

Process finished with exit code 0

*/