void BinarySearchTree::draw( tree t)
{
        queue <tree> levelOrder;
        levelOrder.push(t);
                
        while(!levelOrder.empty())
        {       
                cout << levelOrder.front()->getKey() << endl;
                if(levelOrder.front() != NULL)
                {
                        levelOrder.push(levelOrder.front()->left);
                        levelOrder.push(levelOrder.front()->right);
                }
                levelOrder.pop();
        }

}