class Book
  attr_reader :id, :title
  def initialize(id, title)
    @id = id
    @title = title
  end
end
 
bookShelf = []
 
bookShelf <<
  Book.new(1, "English") <<
  Book.new(2, "Math") <<
  Book.new(3, "History") <<
  Book.new(4, "Physics") <<
  Book.new(5, "Programming") <<
  Book.new(6, "Science")
 
print "------- Order -------\n"
 
bookShelf.each{ | book | print "id: #{book.id} title: #{book.title}\n" }
 
print "------- Reverse Order -------\n"
 
bookShelf.reverse_each{ | book | print "id: #{book.id} title: #{book.title}\n" }

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