4.1.2 FoP (Programming Paradigms)

Question 1

What is meant by a Class

Answer 1

Software blueprint or template for implementing objects of a given type which specifies that data fields and methods that objects will have

Question 2

What is an Object

Answer 2

An instance of a class, that has a collection of of data fields and methods that operate on these data fields

Question 3

What is meant by the term Encapsulation

Answer 3

The practice and ability to hide or isolate the internal components (data) and operations (methods) of an object, allowing the user only to communicate only through the public interface.

Question 4

What is it meant for an object to be ‘black-boxed’

Answer 4

If an object is properly encapsulated, it will only reveal the information needed to reuse its members through the public interface

Question 5

What is meant by the term inheritance

Answer 5

The relationship among classes wherein one class shares the data structure and behaviours of another, meaning it has the same properties and methods as its parent class.

Question 6

What is meant by Polymorphism

Answer 6

It refers to the programming language’s ability to process objects differently depending on class or data type

Question 7

What is Inheritance based Polymorphism

Answer 7

A situation when the method in the base class is inherited in the derived class, but is redefined to suit the data and purpose of the derived class.

Question 8

What is meant by Method Overloading

Answer 8

When multiple methods in the same class have the same name but a different parameter list.

Question 8

What is meant by Overriding

Answer 8

Methods will allow a derived class to alter the behaviour that is inherited from the base class, whilst maintaining the same method call and signature.

Question 9

What is Interface based Polymorphism

Answer 9

When an interface is created and is implemented differently in several classes, making the method call the same but the algorithm potentially differently

Question 10

What is meant by Aggregation

Answer 10

When an object may be built up from other objects, and is based on the way in which objects are related

Question 11

What is Association Aggregation

Answer 11

When an object has a relation but no dependency on the existence of another object (if one is destroyed the other still exists)

Question 12

What is Composition Aggregation

Answer 12

When an object has a relation an dependency on the existence of another object (if one is destroyed the other no longer exists)

Question 13

What are the three Advanced Design Principles

Answer 13

• Encapsulates What Varies
• Favour Composition over Inheritance
• Program to interfaces, not Implementation

Question 14

What does it mean to Encapsulate What Varies

Answer 14

The idea that where there is a variance, there should be a class for it

Question 15

What does it mean to Favour Composition Over Inheritance

Answer 15

Instead of building complex inheritance hierarchies, programmers should create stand-alone classes that combine with other classes to produce efficient code.

Question 16

What does it mean to Program to interfaces, not implementation?

Answer 16

Allows programs to be written based on interfaces as opposed to each individual implementation of a class. This allowsus to alter individual classes without directly affecting the class, by modifying the functionality, with reference to the interface