/** * Decrements the given {@code NaturalNumber}. * * @param n * the number to decrement * @updates n * @requires n > 0 * @ensures n = #n - 1 */ private static void decrement(NaturalNumber n) { assert n != null : "Violation of: n is not null"; assert !n.isZero() : "Violation of: n > 0"; // TODO - fill in body }