From: Rob Biedenharn <Rob@...>
Date: 2008-10-11T01:07:43+09:00
Subject: Re: [QUIZ] Modular Arithmetic (#179)


On Oct 10, 2008, at 11:13 AM, Matthew Moss wrote:

>   # The default modulus is 26.
>   > a = Modulo.new(15)
>   > b = Modulo.new(19)
>   > puts (a + b)
>   8
>   > puts (a - b)
>   22
>   > puts (b * 3)
>   5
>
> As noted in the example, you should use a modulus of 26 if none is  
> specified in the initializer.

>      def test_mul_int_reverse
>         a = Modulo.new(15, 8)
>         assert_equal(77, 11 * a)
>      end
>
>      def test_non_default_modulo
>         a = Modulo.new(15, 11)
>         b = Modulo.new(9, 11)
>
>         assert_equal(2, a + b)
>         assert_equal(6, a - b)
>         assert_equal(3, a * b)
>      end

So I suppose the method signature would be documented something like:

-------------------------------------------------------------  
Modulo::new
      Modulo.new(value=0, modulus=26)
------------------------------------------------------------------------
      Returns a new object that behaves according to the rules of
      Modular Arithmetic, but otherwise responds like an Integer from
      the set of integers between 0 and modulus-1.


You never specifically said how an alternate modulus was indicated,
but your tests give a good hint.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com