difference_between_private_and_protected.rb

# difference between private and protected in Ruby

class Person

  def initialize age
    @age = age
  end

  def compare1(another_person)
    #            this works because #age is protected
    self.age <=> another_person.age
  end

  def compare2(another_person)
    #            this fails because #age2 is private
    self.age2 <=> another_person.age2
  end


  protected

  def age
    @age
  end

  private

  def age2
    @age
  end

end


peter = Person.new(42)

mary = Person.new(30)

puts peter.compare1(mary)

# This throws an exception!!!
puts peter.compare2(mary)