cc_algorithm

# Don't forget to check on intialization for a card length
# of exactly 16 digits
class CreditCard
  def initialize(cc)
    @cc_int = []
    raise ArgumentError.new("CC Number is not 16 Digits") if cc.to_s.length != 16
    cc.to_s.each_char { |ch| @cc_int << ch.to_i if ch != ' ' }
  end
  
  def check_card
    @cc_int.each_with_index { |val, index| index % 2 == 0 ? @cc_int[index]=val*2:@cc_int[index]=val }
    (@cc_int.inject(0) { |result, value| value >= 10 ? result + value.to_s[1].to_i + 1:(result + value) }) % 10 == 0
  end
end


#VERSUS

# Don't forget to check on intialization for a card length
# of exactly 16 digits
class CreditCard
  def initialize(cc)
    @cc_str = cc.to_s
    @cc_int = []
    for i in 0...@cc_str.length
      @cc_int << @cc_str[i].to_i if @cc_str[i] != ' '
    end
    raise ArgumentError.new("CC Number is not 16 Digits") if @cc_str.length != 16
  end
  
  def check_card
    step_1 = @cc_int
    for i in 0..15
      step_1[i] = step_1[i]*2 if i % 2 == 0
    end
    runsum = 0
    for i in 0..15
      if step_1[i] >= 10
        runsum += step_1[i] % 10 + 1
      else
        runsum += step_1[i]
      end
    end
    runsum % 10 == 0
  end
end