module BookKeeping
  VERSION = 3
end

class Raindrops
  def self.convert(i)
    new(i).convert
  end

  attr_reader :number
  def initialize(number)
    @number = number
  end

  def convert
    unless pling? || plang? || plong?
      return number.to_s
    end

    s = ''
    s << 'Pling' if pling?
    s << 'Plang' if plang?
    s << 'Plong' if plong?
    s
  end

  private

  def pling?
    (number % 3) == 0
  end

  def plang?
    (number % 5) == 0
  end

  def plong?
    (number % 7) == 0
  end
end