steak.rb

class Steak

  GRADE_SCORES = {"Prime" => 3, "Choice" =>2, "Select" => 1}

  include Comparable

  attr_accessor :grade

  def <=> (other)
    if GRADE_SCORES[self.grade] < GRADE_SCORES[other.grade]
      return -1
    elsif GRADE_SCORES[self.grade] == GRADE_SCORES[other.grade]
  	  return 0
    else
  	  return 1
    end
  end

end

first_steak = Steak.new
first_steak.grade = "Prime"
second_steak = Steak.new
second_steak.grade = "Choice"

prime = Steak.new
prime.grade = "Prime"
choice = Steak.new
choice.grade = "Choice"
select = Steak.new
select.grade = "Select"

puts "prime > choice: #{prime > choice}"
puts "prime < select: #{prime < select}"
puts "select == select: #{select == select}"
puts "select <= select: #{select <= select}"
puts "select >= choice: #{select >= choice}"
print "choice.between?(select, prime): "
puts choice.between?(select, prime)