The cause of Cushing's syndrome boils down to: Your body is exposed to too much cortisol. There are a few ways that this over-exposure can happen, including taking certain medications and having a tumor on your pituitary gland or adrenal gland.
Difference between class and instance variables. Now, it should be clear what the difference between instance and class variables is. Class variables only have one copy that is shared by all the different objects of a class, whereas every object has itâs own personal copy of an instance variable. So, instance variables across different objects can have different values whereas class variables across different objects can have only one value.
A class variable (@@) is shared among the class and all of its descendants. A class instance variable (@) is not shared by the class's descendants. Class variable (@@). Let's have a class Foo with a class variable @@i, and accessors for reading and writing @@i: And a derived class: