[QUIZ] Checking Credit Cards (#122)

Ruby
1

This is my first submission to Ruby Q…

I have all the credit card rules in an external YAML file. I also think
that my luhn() and type() implementations could be cleaner, but it is
what
it is. :slight_smile:

ccard.yaml

Visa: { starts: [ ‘4’ ],
sizes: [ 16, 13 ] }
MasterCard: { starts: [ ‘51’, ‘52’, ‘52’, ‘54’, ‘55’ ],
sizes: [ 16 ] }
Discover: { starts: [ ‘6011’ ],
sizes: [ 16 ] }
American Express: { starts: [ ‘34’, ‘37’ ],
sizes: [ 15 ] }

ccard.rb

Credit Card Validation

Ruby Q. #122 - Ruby Quiz - Checking Credit Cards (#122)

By Mike M. - http://blowmage.com/

require ‘yaml’

class CreditCard
def CreditCard.luhn(cc)
multi = 1
nums = cc.gsub(/\D/, ‘’).reverse.split(‘’).collect do |num|
num = num.to_i * (multi = (multi == 1) ? 2 : 1)
end
total = 0
nums.join.split(‘’).each do |num|
total += num.to_i
end
total
end

def CreditCard.valid?(cc)
(CreditCard.luhn(cc) % 10) == 0
end

def CreditCard.type(cc)
cc.gsub!(/\D/, ‘’)
YAML::load(open(‘ccard.yaml’)).each do |card, rule|
rule[‘starts’].each do |start|
if (cc.index(start.to_s) == 0)
return card if rule[‘sizes’].index(cc.size)
end
end
end
‘Unknown’
end

def initialize(cc)
@number = cc.gsub(/\D/, ‘’)
end

def number
@number
end

def number=(cc)
@number = cc.gsub(/\D/, ‘’)
end

def valid?
CreditCard.valid? @number
end

def type
CreditCard.type @number
end
end

if FILE == $0
cc = CreditCard.new ARGV.join
puts “You entered the following credit card number: #{cc.number}”
puts “The number is for a #{cc.type} credit card”
puts “The number is #{cc.valid? ? ‘Valid’ : ‘Not Valid’}”
end