Classes and Encupsulation

Question 1

3 Fundamental Principles of Object-Oriented Programming

Answer 1

1. Encapsulation.
2. Inheritance.
3. Polymorphism.

Question 2

Encapsulation

Answer 2

Concept of hiding values or state of data within a class, limiting the points of access.

Question 3

Inheritance

Answer 3

The practice of creating a hierarchy for classes in which descendants obtain the attributes and behaviors from other classes.

Question 4

Polymorphism

Answer 4

The ability for a code to take on different forms. In other words, it’s the ability to treat classes generically and get specific results.

Question 5

Benefits of Object-Oriented Programming

Answer 5

1. A natural way of expressing real-world objects in code.
2. Modular and reliable, allowing changes to be made in one part of the code without affecting another.
3. Discrete units of reusable code.
4. Units of code can communicate with each other by sending and receiving messages and processing data.

Question 6

Encapsulation characteristics

Answer 6

1. The packaging of data and functions into a single component.
2. Hiding the implementation details of a class to prevent other parties from setting the data to an invalid or inconsistent state and also to reduce coupling.
3. Enables classes to be highly cohesive, meaning to have a clearly defined purpose.
4. Implemented by using access modifiers that let the compiler know which data members and methods can be accessed and modified by others.

Question 7

Coupling

Answer 7

Coupling refers to the degree of direct knowledge each component of a system or application has of elements that it needs to use.

Question 8

Loose Coupling

Answer 8

An approach to connect components that depend on each other with the least knowledge possible.

Question 9

Access modifiers

Answer 9

Visibility of classes, member methods, and variables
Defines who can use a class, method, or variable.
- public
- private

Question 10

Variables

Answer 10

Should always be private. If the others need access to them, then they should be given access via public getters and setters.

Question 11

Methods

Answer 11

Should be public only if they are meant for use by the users of our class.

Question 12

Classes

Answer 12

Is a blueprint or model that defines state with fields (variables) and behavior with methods.

Question 13

Methods

Answer 13

Reusable block of code. Define object’s behaviors.

Question 14

OOP

Answer 14

Object-Oriented Programming

Question 15

Overloaded methods

Answer 15

Methods with the same name and return type, and a different set of parameters.

Question 16

Constructor

Answer 16

Is a special method that runs every time a new object is instantiated.

Question 17

Function Overriding

Answer 17

Provide own functionality for the subclasses’ method.

Question 18

Final

Answer 18

A keyword that allows the variable to be assigned once, and after set, it cannot be reassigned.

Question 19

Static

Answer 19

Static members belong to the class. Static methods can be invoked without creating an instance of the class.