gistfile1.rb

class BookInStock
  attr_reader :isbn
  attr_accessor :price
  def initialize(isbn, price)
    @isbn = isbn
    @price = Float(price)
  end
  def price_in_cents
    Integer(price*100 + 0.5)
  end
  def price_in_cents=(cents)
    @price = cents / 100.0
  end
  # ...
end