gistfile1.txt

# define class Dog
class Dog
  attr_accessor :breed, :name

  def initialize(breed, name)
    # Instance variables
    @breed = breed
    @name = name
  end


  def bark
    puts 'Ruff! Ruff!'
  end

  def display
    puts "I am of #{@breed} breed and my name is #{@name}"
  end



  # def name
  #   @name
  # end

  # def breed
  #   @breed
  # end

  # def name=(local_variable)
  #   @name = local_variable
  # end

  # def breed=(local_variable)
  #   @breed = local_variable
  # end

end

# make an object
# Objects are created on the heap
# d = Dog.new('Labrador', 'Benzy')


my_shiny_new_dog = Dog.new('Labrador', 'Benzy')
=begin
  Every object is "born" with certain innate abilities.
  To see a list of innate methods, you can call the methods
  method (and throw in a sort operation, to make it
  easier to browse visually). Remove the comment and execute.
=end
# puts d.methods.sort

# Amongst these many methods, the methods object_id and respond_to? are important.
# Every object in Ruby has a unique id number associated with it
puts "The id of d is #{d.object_id}."

# To know whether the object knows how to handle the message you want
# to send it, by using the respond_to? method.
if d.respond_to?("talk")
  d.talk
else
  puts "Sorry, d doesn't understand the 'talk' message."
end

d.bark
d.display

# making d and d1 point to the same object
d1 = d
d1.display

# making d a nil reference, meaning it does not refer to anything
d = nil
d.display

# If I now say
d1 = nil
# then the Dog object is abandoned and eligible for Garbage Collection (GC)



class Cat

  attr_accessor :breed, :name

  def initialize(breed, name)
    # Instance variables
    @breed = breed
    @name = name
  end

  def meow
    puts 'Meow! Meow!'
  end

  def display
    puts "I am of #{@breed} breed and my name is #{@name}"
  end
end

my_newer_and_even_shinier_cat = Cat.new('Persian', 'Kitty')