CSC301: Printing: Print postfix with a loop [26/30]

    public void printPost () {
        Stack<int>  r = new Stack<> ();  // keys to print out
        Stack<Node> s = new Stack<> ();  // nodes for the traversal
        s.push (root);
        while (!s.isEmpty ()) {
            Node x = s.pop ();
            if (x == null) continue;
            r.push (x.key);
            s.push (x.left);
            s.push (x.right);
        }
        while (!r.isEmpty ())
            StdOut.print (r.pop () + " ");
        StdOut.println ();
    }

Print postfix with a loop

Hmmm.