Fwd: Please Forward: Ruby Quiz Submission

Ruby
1

Begin forwarded message:

2

Here’s my solution:

#!/usr/bin/env ruby

def type(card)
if card =~ /\A4(\d{12}|\d{15})\Z/
“VISA”
elsif card =~ /\A3(4|7)\d{13}\Z/
“AMEX”
elsif card =~ /\A5[1-5]\d{14}\Z/
“MasterCard”
elsif card =~ /\A6011\d{12}\Z/
“Discover”
else
“Unknown”
end
end

def luhn_valid?(card)
digits = card.unpack(“c#{card.length}”).map { |c| c.chr.to_i }
sum = 0
digits.each_with_index do |n, i|
val = if i % 2 == digits.length % 2
2 * n
else
n
end

sum += if val >= 10
  1 + (val % 10)
else
  val
end

end
sum % 10 == 0
end

def valid?(card)
card_type = type(card)
puts “#{card_type} - #{ (card_type != “Unknown” && luhn_valid?
(card)) ? “Valid” : “Invalid” }”
end

valid?(ARGV[0])