Object-Oriented Languages
Computer Science: OCR A Level, topic 2.4.8
Object-Oriented Languages
Object-oriented programming allows us to model real-world objects and manipulate them easily.
Object-oriented programming
- In object-oriented programming, most real-world objects, like cars, can be modelled.
- Each object is an instance of the class. Objects contain:
- Attributes: things we store about them e.g. the make and model of the car.
- Methods: things the object can do e.g. starting the engine or indicating to turn.
Classes
- A class forms a blueprint that we can use to instantiate (create) an object.
- A car class could be instantiated for every car ever made.
- Each object would have the same behaviours, but slightly different values in their attributes.
Inheritance
- We can define a subclass from what we call the 'super class'.
- These are sometimes known as child class and parent class.
- In inheritance, the subclass inherits all of the attributes and methods of the superclass.
- The subclass can have its own attributes and methods.
Example
- If we had a vehicle super class, we could have a subclass of car that would inherit all of the attributes and methods of the vehicle class.
- The car subclass could add additional attributes such as colour and methods such as indicate_left that do not apply to the vehicle super class.
Test yourself on Object-Oriented Languages
Which of the following is true of inheritance?