basic discounter

discounter.rb

class Discounter
  def discount(*skus)
    expensive_calc(skus)
  end

  private
  def expensive_calc(*skus)
    puts "in expensive calc for #{skus}"
    skus.inject{|m,n| m + n}
  end
end

d = Discounter.new
d.discount(1,2,3)
d.discount(1,2,3)
d.discount(4,2,3)
d.discount(4,2,3)