From: Daniel Martin <martin@...>
Date: 2007-04-27T21:36:15+09:00
Subject: Re: [QUIZ] Checking Credit Cards (#122)

Ruby Quiz <james@grayproductions.net> writes:

> This week's Ruby Quiz is to write a program that accepts a credit
> card number as a command-line argument.  The program should print
> the card's type (or Unknown) as well a Valid/Invalid indication of
> whether or not the card passes the Luhn algorithm.

May I make an additional suggestion?  Treat spaces in the card number
as perfectly valid, and simply strip them before processing.  One of
the most irritating features found in many online stores is the
requirement that the credit card number be typed in with no spaces.
(The other biggie is using a select box for the state abbreviation)

Now granted, for accepting the card number from the command line this
will mean that on the command line the card number was quoted, but
presumably most people's programs will be a command-line wrapper
around a function/class that does the real work.

-- 
s=%q(  Daniel Martin -- martin@snowplow.org
       puts "s=%q(#{s})",s.to_a[1]       )
       puts "s=%q(#{s})",s.to_a[1]