From: incag neato <lists@...>
Date: 2012-08-29T11:58:15+09:00
Subject: What is happening here, Batman?

Hello! Been working thru Chris Pine's book for noobies to ruby, and got
to the roman-numeral question. This one is new to me, given the material
thus far.

> def old_roman_numeral num
>     roman = ''
>     roman = roman + 'D' * (num % 1000 / 500)
>     roman = roman + 'C' * (num % 500 / 100)
>     roman = roman + 'L' * (num % 100 / 50)
>     roman = roman + 'X' * (num % 50 / 10)
>     roman = roman + 'V' * (num % 10 / 5)
>     roman = roman + 'I' * (num % 5 / 1)
>     roman
> end
> puts(old_roman_numeral(1999))

I have broken this code down into pieces to understand what's happening,
but still a little fuzzy.

I have a decent grasp on the modulus operator and multiplying strings.

1) But, when I pass the integer (1999 in this case) thru, what exactly
is happening? Is it simply "picked up" by roman = '' and run thru?

2) And what's the significance of the final "roman" before 'end'?

3) Also, how can one deduce the necessity to divide again after applying
the modulus op? (E.g. 500, 100, 50, 10, etc.) I feel like I've opened a
calculator and I just don't 'get' how it was engineered.

I appreciate your effort in helping me understand!!

-- 
Posted via http://www.ruby-forum.com/.