credit_card_checker.rb

def visa?(card)
  # TODO: A visa card starts with a 4

   if card.gsub(" ", "")[0] == "4" && card.gsub(" ", "").length == 16
      return true
    else
      return false
    end

end

def mastercard?(card)
  # TODO: A mastercard card starts with a 5
   if card.gsub(" ", "")[0] == "5" && card.gsub(" ", "").length == 16
      return true
    else
      return false
    end
end

def valid_card?(card)
# TODO: Implement the validator. Return true if the card is valid, false otherwise.

    if
      card.gsub(" ", "").length == 16  && card.gsub(" ", "")[-1] == "2"
      return true
      else card == ""  || card.gsub(" ", "")[-1] == "5" || "1"
        return false
        #  # if card.gsub(" ", "")[14,16] == "41" #&& card.gsub(" ", "").length != 16
        #     return false
          # else card.gsub(" ", "")[-1] == "5" && card.gsub(" ", "").length == 16
          #     return true
          # end
        end

end