Re: Checking Credit Cards (#122)

Ruby
1

class CreditCardNumberValidator

CARD_TYPE =  {
    :amex => 'AMEX',
    :discover => 'DISCOVER',
    :master_card => 'MASTER CARD',
    :visa => 'VISA',
    :unknown =>  'UNKNOWN'
}

CARD_NUMBER_PATTERN = {
    :amex => /^3[4|7][0-9]{13}$/,
    :discover => /^6011[0-9]{12}$/,
    :master_card => /^5[1-5][0-9]{14}$/,
    :visa => /^4[0-9]{12}$|^4[0-9]{15}$/
}


def self.card_type(card_num)
    CARD_NUMBER_PATTERN.each do |t, p|
        return CARD_TYPE[t] if card_num =~ p
    end
    CARD_TYPE[:unknown]
end

def self.valid?(card_num)
    sum = 0
    card_num.to_s.reverse.scan(/./).each_with_index do |digit,

index|
digit = digit.to_i * (1 + (index % 2))
sum+=digit/10 + digit%10;
end
sum % 10 == 0
end
end

abort “Usage: #{$0} number” unless ARGV.length > 0
card_num = ARGV.join.to_i
puts “Number: #{card_num}”
puts 'Type: ’ + CreditCardNumberValidator.card_type(card_num)
puts 'Validation: ’ + (CreditCardNumberValidator.valid
?(card_num)?‘Valid’:‘Invalid’)