うーん。原因がわからない。

class Book
	attr_accessor :author,:title
	def initialize(args)
		@author= args[:author]
		@title=args[:title]
		args[:library] << self
	end

	def to_s
		puts "Title:" + @title + ", Author: " + @author
	end

end


class Library
	def initialize
		@books = []
	end

	def <<(book)
		@books << book
	end

	def to_s
		puts "Library contents:"
		@books.join("/n")
	end
end


my_library = Library.new
Book.new(:author => "Herman Melville", :title => "Moby-Dick", :library => my_library)
Book.new(:author => "Hans Christian Andersen", :title => "The Ugly Duckling", :library => my_library)
puts my_library

result:
$ ruby en01.rb
Library contents:
Title:Moby-Dick, Author: Herman Melville
Title:The Ugly Duckling, Author: Hans Christian Andersen
#/n#


最後のなんだ?