OOP

Question 1

What is a class

Answer 1

A class is a template for an object and defines the state and behaviour of an object

Question 2

How are the state and behaviour of an object defined

Answer 2

• State- given by attributes which give an object’s properties
• Behaviour - given by the methods associated with a class, which describe the actions it can perform

Question 3

What is an object

Answer 3

An object is a particular instance of a class

Question 4

What are setters and getters

Answer 4

• A setter is a method that sets the value of a particular attribute
• A getter is a method which retrieves the value of a given attribute

Question 5

Why are getters and setters used

Answer 5

• To make sure attributes cannot be directly accessed and edited by users
• Attributes are declared as private so can only be altered by public methods
• Every class must also have a constructor method, which is called ‘new​’. A constructor allows a new object to be created

Question 6

What is encapsulation

Answer 6

A property of object-oriented programming which makes it so attributes cannot be directly accessed and edited by users

Question 7

What is Inheritance

Answer 7

• A property of object-oriented programming.
• Due to inhertaince a class can inherit from another class
• The subclass will possess all of the methods and attributes of the superclass

Question 8

What is Polymorphism

Answer 8

• A property of OOP that means objects can behave differently depending on their class.
• This can result in the same method producing different outputs depending on the object involved

Question 9

What is overriding and overloading

Answer 9

• Overriding - redefining a method within a subclass and altering the code so that it functions differently and produces a different output
• Overloading - passing in different parameters into a method

Question 10

What are the advantages of Object-Oriented Programming (OOP)

Answer 10

• Polymorphism and Inheritance - these properties allow OOP for a high level of reusability, which makes it useful for projects where there are multiple components with similar properties.
• Encapsulation - makes the code more reliable by protecting attributes from being directly accessed
• Faster - code for different classes can also be produced independently of others
• Adavanced Planning - OOP requires advance planning to determine how the problem will be broken down into classes and how these will link to each other. A thorough design can produce a higher-quality piece of software with fewer vulnerabilities. - The modular structure used in OOP makes it easy to maintain and update.
• Abstraction- it is not necessary for programmers to know details about how code is implemented. Once classes have been created and tested, they can be reused as a black box which saves time and effort

Question 11

What are the disadvantages of Object-Oriented Programming (OOP)

Answer 11

• This is a different style of programming and so requires an alternative style of thinking. This can be difficult for programmers accustomed to other paradigms to pick up.
• Small Projects - Generally unsuitable for smaller problems, OOP is not suited to all types of problems. Where few components are reused, OOP may in fact result in a longer, more inefficient program.