Why Learn About Object-Oriented Programming Languages?

Written by Coursera Staff • Updated on

Object-oriented programming (OOP) has become popular for building new programs. Learn more about its principles and benefits and some popular OOP languages.

[Featured image] A person wearing a sweatshirt and headphones works with object-oriented programming languages on a desktop computer.

Object-oriented programming (OOP) is a way of thinking about and organising code for maximum reusability. With this type of programming, a program comprises objects that can interact with the user, other objects, or other programs. This makes programs more efficient and easier to understand. 

OOP follows four basic principles: 

  • Encapsulation: Data and methods that interact with that data are bundled into one unit. This allows you to control access to the data within each object.

  • Abstraction: When creating an object, the coder reduces complexity by showing only essential information and 'hiding' everything else, including implementation mechanisms.

  • Inheritance: A programmer can derive a new object with all or some of the properties of an existing object. For example, a child class will inherit properties and behaviours from a parent class.

  • Polymorphism: This allows us to use child and parent classes in precisely the same way while maintaining each class's unique attributes.

Object-oriented programming vs. functional programming

Object-oriented and functional programming aims to develop flexible programs that are easy to understand while minimising the possibility of bugs. They are, however, based on very different approaches.

Object-oriented programming languages make understanding how a program works easier by bringing together data and its behaviour (or method) in a single bundle called an “object.” 

Functional programming is a model based on performing operations, or functions, on static data. This is based on the idea that data and behaviour are different entities and should be kept separate to avoid confusion.


Advantages of object-oriented programming

Programs made with object-oriented programming are well organised. Since relative data and functions are grouped in the same object, it is easier to find what you are looking for and get a basic idea of the code's purpose. Developers new to the project or those revisiting code they have not seen in a while can get their bearings more quickly. Since the code is divided into manageable pieces, you can avoid the overwhelming monolith files that become unwieldy and unnecessarily complicated.

Let's take a closer look at some of the advantages of object-oriented programming:

1. Reusability

Abstraction gives you the ability to reuse code throughout the project. It cuts down on file size and overhead for your brain. Knowing you can call a method in an existing and flexible object means you do not have to rewrite it in another part of the codebase. You can also use self-contained objects in other codebases to speed up development in new projects. 

This becomes even more useful if you make a library or framework out of low-level utility objects that could be used for any project. Something like authentication or activity logging would be a useful library, gem, or package (the name will differ depending on your language). Not only are you efficiently sharing code within your project or team, but this also enables you to share it with anyone. This is how open-source software works.

2. Testing and debugging

The self-contained nature of object-oriented programming lends itself well to testing. Writing tests for specific pieces of your project becomes straightforward when the objects are only concerned with the functions and data they contain.

3. Flexibility

Object-oriented programming provides flexibility for your codebase through inheritance and polymorphism. Classes and objects (depending on the language) can also share properties and methods through inheritance. The child class or object inherits everything from its parent. When a child redefines something inherited from a parent, it is polymorphism.

Here’s an example: if you have an object called a vehicle with a property of several wheels and a method called drive, then you could create a child object called a motorcycle. Motorcycles would inherit drive and number of wheels, but you could update several wheels to have a value of '2'. If you ever update the method called drive on the vehicle object, then every child object (like a motorcycle, scooter, or bus) would have the new drive method.

Inheritance works for every generation, not just direct parent-child relationships. If you created a child of a motorcycle called a cruiser, it would inherit everything the motorcycle has and every method and property that the vehicle object contains. This feature adds a lot of reusability if you keep your common functions and values in your lower-level objects.

This can be beneficial but lead to unintended issues if you are more careful. You only have to update one function on the parent to update all children, but you may update many children you did not intend to update.

Several popular programming languages lend themselves to object-oriented programming. It's possible to bundle data and behaviours into individual objects in each of these languages. If you're considering learning an OOP language, here are three to consider:

  • Java: Java ranks among the oldest and most popular object-oriented languages thanks to its easy learning curve and robust security features. Consider learning Java if you're interested in back-end development, particularly for Android devices.

  • Python: Python is easy to learn, read, and versatile; it's an excellent choice for beginners or those who need help deciding what coding career they want to pursue.

  • C#: C# (pronounced C Sharp) is popular for developing games, desktops, and web applications, particularly on the Microsoft platform. 

Careers that involve OOP languages

Programmers use OOP languages to develop games, mobile apps, and websites. Here are some careers you might consider once you've learned an OOP language:

*All salary data is sourced from Glassdoor as of April 2024.

  • Software developer: ₹25,70,000

  • Game developer: ₹24,74,874 

  • iOS applications developer: ₹7,86,924

  • Android developer: ₹8,11,439

  • Full-stack developer:  ₹8,19,298

Learn object-oriented programming

Build in-demand development skills by learning a new OOP language at your own pace through top universities and industry leaders on Coursera. Learn object-oriented programming in Java from Duke University, Python for everybody from the University of Michigan, and C# programming for Unity Game Development from the University of Colorado Boulder.

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