public static <T> void print_BST_in_sorted_order(BinarySearchTree<T> n) {
        LinkedList<BinarySearchTree<T>> s = new LinkedList<BinarySearchTree<T>>();
        BinarySearchTree<T> curr = n;

        while(!s.isEmpty() || curr != null) {
            if(curr != null) {
                s.push(curr);
                curr = curr.getLeft();
            } else {
                curr = s.pop();
                System.out.println(curr.getData());
                curr = curr.getRight();
            }
        }
    }