Ruby Fundamental - Um pouco sobre classes (parte I)

classes_01.rb

class Dog

end

classes_02.rb

d = Dog.new

classes_03.rb

class Dog
  def bark
    puts "Au, au, au!"
  end

  def sleep
    puts "Zzzzzzz..."
  end
end

classes_04.rb

d = Dog.new
d.sleep # => Zzzzzzz...
d.bark  # => Au, au, au!

classes_05.rb

class Dog
  def initialize(name, breed)
    @name, @breed = name, breed
  end

  def bark
    puts "Au, au, au!"
  end

  def sleep
    puts "Zzzzzzz..."
  end
end

classes_06.rb

d = Dog.new "Snoopy", "Beagle"

classes_07.rb

d = Dog.new
# => ArgumentError: wrong number of arguments (0 for 2)

classes_08.rb

class Dog
  def initialize(name, breed)
    @name, @breed = name, breed
  end

  def bark
    puts "Au, au, au!"
  end

  def sleep
    puts "Zzzzzzz..."
  end

  def to_s
    "#{@name} is a #{@breed}."
  end
end

classes_09.rb

snoopy = Dog.new "Snoopy", "Beagle"
pixel = Dog.new "Pixel", "Yorkshire"
puts snoopy # => Snoopy is a Beagle.
puts pixel  # => Pixel is a Yorkshire.

classes_10.rb

puts snoopy
puts snoopy.to_s