CSC301: Printing: Print postfix [24/30]

    public void printPost () {
        printPost (root);
        StdOut.println ();
    }
    private static void printPost (Node x) {
        if (x == null) return;
        printPost (x.left);
        printPost (x.right);
        StdOut.print (x.key + " ");
    }

Yeah!

What about using a loop?