# Computing - Object Oriented Programming

> Source: https://ollybritton.com/notes/a-level/computing/topics/object-oriented-programming/ · Updated: 2024-08-25 · Tags: computing

##### What is a class??
A blueprint or template for a type of object.

##### What are the data of an object called??
Attributes.

##### What are the operations that you can perform on object called??
Methods.

##### What is instantiation??
Creating an object from a class.

##### What is the concept of encapsulation??
Attributes and methods are wrapped into a single entity.

##### What is inheritance??
Where subclasses use attributes and methods of it's superclass.

##### What is the Python syntax for initialising the superclass??
```python
super().__init__(params...)
```

### 2021-11-08
##### What is a "record" pretty similar too??
A class.

### 2022-06-05
##### Does an object or a class define methods in OOP??
A class.

##### What is an object??
A specific instance of a class.

##### What are the three sections of a class in a class diagram??
![PHOTO CLASS DIAGRAM BOX](paste-c17c5b8278a3898080eb429a06d9e5eb85354eb7.jpg)

##### What do the direction of arrows show in a class diagram??
Source inherits destination.

##### What does a "+" mean in a class diagram??
This is a public method/attribute.

##### What does a "-" mean in a class diagram??
This is a private method/attribute.

##### What is the difference between private and protected methods/attributes??
Private means it can only be accessed inside the class where it's defined, whereas protected means it can be accessed by all subclasses too.

##### What is polymorphism??
The ability of different types of data to be manipulated with the same method.

##### What is overriding??
Where a method in a subclass takes precedence over a method with the same name in the base class.

##### What is a static method??
A method that can be used without an object of the class being instantiated.

##### What is a virtual method??
A method defined in the base class that can be overridden in the subclass.

##### What is an abstract method??
A method not supplied in the base class but defined in the subclass.

##### What is an example of an abstract method in the skeleton program??
The `Process` method for a card.

##### What is aggregation in OOP??
Creating objects that contain other sorts of objects.

##### What is composition aggregation??
Creating objects that contains other objects, with the children objects dependent on the parent objects for their existence.

##### What is association aggregation??
Creating objects that contain other objects, with the children being able to survive if the parent doesn't exist.

##### Which type of aggregation means that children will still exist if the parent doesn't exist??
Association aggregation.

##### What type of aggregation means that children won't exist if the parent doesn't exist??
Composition aggregation.

##### ![PHOTO COMPOSITION AGGREGATION CLASS DIAGRAM](paste-28bbd4f58b88cc69e43a91e5347acb40005afdc5.jpg) What type of aggregation is represented by a solid black diamond??
Composition aggregation.

##### ![PHOTO ASSOCIATION AGGREGATION CLASS DIAGRAM](paste-28bbd4f58b88cc69e43a91e5347acb40005afdc5.jpg) What type of aggregation is represented by a hollow diamond??
Association aggregation.

---
Olly Britton — https://ollybritton.com. Machine-readable index: https://ollybritton.com/llms.txt