=begin
Only one variable @@count exists in the class - it's known
as a static of class variable. But two variables exist called
@count - one for each class member. So they're known as
object or dynamic variables.

The getcount method is a dynamic or object method and can use
both object and class variables. But the allcount method is a
class or static method and can only refer to class or static
variables.
=end

class Thing
        @@count = 0
        def initialize(v)
                @@count += 1
                @count = v
        end
        def getcount
                return [@count,@@count]
        end
        def self.allcount
                return [@@count]
        end
end

this = Thing.new(5)
p this.getcount
p Thing::allcount

that = Thing.new(9)
p this.getcount
p that.getcount
p Thing::allcount

# Note :: and . mean the same thing - but it's accepted common
# practise to use :: on a static class member call, and . on a
# dynamic object call.

# If I want to call a static method on a class member (i.e. to
# ask something in general about the class of which an object is
# a member, I can do so by using the .class method on the object
# then calling the static method on the class:

p this.class.allcount