OOP questions

• Can modify and maintain existing code more easily. • Reuse of code in other programs through libraries • Clear modular structure with a defined interface -> can abstract and hide away details.

• They have meaningful identifiers which make code easier to follow and maintain • Constants only have to be updated in one place if the value changes.

The child class gains all of the non-private methods of the parent and all of the attributes of the parent.

• Weaker association • The child class cannot exist independently of the parent class • Real-life example: A person in a car

• Stronger association • The child class cannot exist independently of the parent class. • Real-life example: A wheel of a car

• Used to hide data and methods, which prevents them from being accessed and changed. • Distinguishes attributes/methods as public, protected and private.

A method/attribute accessible from outside the class.

Private methods/attribute are accessible in their own class

Using a defined method, e.g. GetSymbol()

Only current class can access methods / attributes.

Python!

Using a setter method. E.g. ChangeSymbolInCell()

When a method in a child class overrides a method or attribute in a parent class.

Allows us to have a function that can take on many forms of its parameters by using overriding. E.g. the built in function len ()

Static attributes are defined for the class and can be accessed without creating an object instance.

The method isn’t supplied in the base class, which forces the method to be implemented in the subclass (child class)

A method that doesn’t need to be accessed through object instantation.

A method defined in a superclass that can be overridden by methods in a subclass.

Virtual methods have implementation, whereas abstract methods do not.

All methods in Python are virtual.

A class containing abstract methods. It enforces classes to have a fixed set of methods, with the methods being run from the class and not the interface.

Have the child class pointing to the parent class using an arrow with its head shaded in.

Using an arrow with its head as a shaded in black diamond.

Using an arrow with its head as a white diamond.