James Gray
5/2/2007 11:54:00 AM
Begin forwarded message:
> From: "Colin A. Bartlett" <colin@kineticweb.com>
> Date: May 2, 2007 3:47:53 AM CDT
> To: <submission@rubyquiz.com>
> Subject: Please Forward: Ruby Quiz Submission
>
> # (C) Copyright 2007, Kinetic Web Solutions, LLC.
> # Licensed under the MIT license.
> # www.opensource.org/licenses/mit-license.php
>
> # Transliterate out anything that's not a digit
> card_number = ARGV[0].tr("^[0-9]","")
>
> def valid?(card_number)
> # Setup a couple of variables to use
> @sum, @digits = 0, ""
> # Split the number into individual digits,
> # then reverse them and pass each and it's index
> # to the block
> card_number.split("").reverse.each_with_index do |n,i|
> if i % 2 == 0
> # If its sequence in the array is even,
> # append the digit to the string
> @digits << n
> else
> # Otherwise, double it first and then
> # append it to the string
> @digits << (n.to_i * 2).to_s
> end
> end
> # Sum up all the individual digits
> @digits.split("").each {|n| @sum = @sum + n.to_i}
> # Determine if it's divisible evenly by 10
> if @sum % 10 == 0
> return true
> else
> return false
> end
> end
>
> def which_card?(card_number)
> # Not too much going on here, just a bunch
> # of regexp to see which card format it matches.
> # Source for these patterns was Wikipedia
> case card_number
> when /^(35[0-9]{14}|(1800|2131)[0-9]{11})$/
> "JCB"
> when /^(5020|5038|6759)[0-9]{12}$/
> "Maestro"
> when /^(6334|6767)([0-9]{12}|[0-9]{14}|[0-9]{15})$/
> "Solo"
> when
> /^((4903|4905|4911|4936|6333|6759)([0-9]{12}|[0-9]{14}|[0-9]{15})|
> (564182|63
> 3110)([0-9]{10}|[0-9]{12}|[0-9]{13}))$/
> "Switch"
> when /^((4917|4913)[0-9]{12}|417500[0-9]{10})$/
> "Visa Electron"
> when /^(34|37)[0-9]{13}$/
> "AMEX"
> when /^6011[0-9]{12}$/
> "Discover"
> when /^5[1-5][0-9]{14}$/
> "MasterCard"
> when /^4([0-9]{12}|[0-9]{15})$/
> "Visa"
> when /^36[0-9]{12}$/
> "Diners Club (International)"
> when /^55[0-9]{12}$/
> "Diners Club (North America)"
> when /^30[0-5]{11}$/
> "Diners Club (Carte Blanche)"
> else
> "Unknown"
> end
> end
>
> # Spit out the results
> puts "Card Number: #{card_number}"
> puts "Valid? #{valid?(card_number)}"
> puts "Card Type: #{which_card?(card_number)}"
>