What are class variables in Ruby?

What are class variables in Ruby?

Class variables in Ruby are variables that are shared among a class and all of its instances. They are defined with two '@@' symbols.

Can you give me an example of how to use class variables?

Sure! Here's a simple example:

class Dog
  @@number_of_dogs = 0

  def initialize(name)
    @name = name
    @@number_of_dogs += 1
  end

  def self.total_dogs
    @@number_of_dogs
  end
end

In this example, @@number_of_dogs keeps track of how many Dog instances have been created.

What’s the difference between class variables and instance variables?

Class variables (with @@) are shared across all instances of a class, while instance variables (with @) are unique to each instance.

Are there any drawbacks to using class variables?

Yes, class variables can lead to unexpected behavior if subclasses modify them, as they are shared across the class hierarchy.