Used in Variable doc in medium

class_var.rb

class Class_var
  # class variable
  @@count = 0
  # will increase class variable count as soon as class is initiated
  def initialize
    @@count += 1
  end

  def output
    @@count
  end
end

# initiate class
object = Class_var.new
object.output  # => 1

# initiate new object
new_object = Class_var.new
# class varaible doesnt reset the value..
# ..it remembers and carries on its value to other objects
new_object.output  # => 2