Module: Luhn

Defined in:
lib/luhn.rb,
lib/luhn/version.rb

Constant Summary collapse

VERSION = 
"0.0.2"

Class Method Summary collapse

Class Method Details

.calculate_check_digit(number) ⇒ Object 



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# File 'lib/luhn.rb', line 15

def calculate_check_digit(number)
  number_without_check_digit = number.to_s[0...-1] + '0'
  doubles = double_digits(number_without_check_digit.to_i)
  sum = sum_of_all(doubles) unless null?(doubles)
  product = sum * 9
  get_check_digit(product)
end

.double_digits(number) ⇒ Object 



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# File 'lib/luhn.rb', line 27

def double_digits(number)
  doubles = []
  digits = all_digits(number).reverse
  digits.each_with_index do |d, i|
    if i.odd?
      sum = d * 2
      if sum && sum > 9
        split_sum   = sum.to_s.split(//).map(&:to_i)
        make_sum    = split_sum.inject { |sum, n| sum + n }
        doubles     << make_sum
      else
        doubles << sum
      end
    else
      doubles << d
    end
  end
  return doubles
end

.get_check_digit(number) ⇒ Object 



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# File 'lib/luhn.rb', line 23

def get_check_digit(number)
  number.to_s[-1].to_i
end

.ping ⇒ Object 



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# File 'lib/luhn.rb', line 7

def ping
  'pong'
end

.valid?(number) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/luhn.rb', line 11

def valid?(number)
  checksum(number)
end