Topic 7 · Object-Oriented Programming (HL)

BLUEPRINT — defines attributes + methods. Does nothing on its own.

Each separate THING created from a class. `d1 = Dog('Rex')`. Many objects per class.

Constructor — runs automatically when object is created. Sets up initial attributes via `self.x = ...`.

Reference to the current object. `self.name` is this object's name; different objects have different selves.

Data stored INSIDE an object. e.g. self.balance, self.name. Each object has its own values.

Function defined INSIDE a class. Called as `obj.method()`. First parameter is always `self`.

`class Sub(Super)` — Sub IS-A Super and inherits Super's attributes + methods.

Subclass defines a method with the SAME NAME as the parent → subclass version is used for its objects.

Same method call → different behaviour depending on object's actual class. Run-time resolution.

Encapsulation · Abstraction · Inheritance · Polymorphism.