node* delete(node* tree, int x)
{
    if (tree == NULL)
    {
        return tree;
    }
    if (x < tree->data)
        //delete node from left subtree
        tree->left = delete(tree->left, x);
    else if (x > tree->data)
        //delete node from right subtree
        tree->right = delete(tree->right, x);

    else
    {

        if (tree->left == NULL)
        {
            node* temp = tree->right;
            free(tree);
            return temp;
        }
        else if (tree->right == NULL)
        {
            node* temp = tree->left;
            free(tree);
            return temp;
        }

        node* temp = min_value_node(tree->right);

        tree->data = temp->data;
        tree->right = delete(tree->right, temp->data);
    }
    return tree;
}