CSC403: Printing: Print level-order in a loop [10/10]

    public void printLevel () {
        Queue<Node> q = new Queue<> ();
        q.enqueue (root);
        while (!q.isEmpty ()) {
            Node x = q.dequeue ();
            if (x == null) continue;
            StdOut.print (x.key + " ");
            q.enqueue (x.left);
            q.enqueue (x.right);
        }
        StdOut.println ();
    }

Print level-order in a loop: not bad

Postfix and infix are bad.