Mastering the Basics: An Introduction to Object-Oriented Programming

If you ever wondered how #Google, #Amazon, and #Apple build their scalable #softwaresystems, then this article is made for you!

Are you familiar with the concept of Object-Oriented Programming (#OOP)?

If it’s not the case, don’t worry, in this article, we’ll tell you more about it and how to start using it in your #software projects. So let’s start with the basics:

What is OOP?

Simply put Objet-Oriented Programming is a method of creating and organizing code that will make it easier for you to maintain it. In other more technical words, OOP is a programming paradigm that focuses on the concepts of objects, their proprieties, and how they come to interact with each other.

Those objects can be seen as the building blocks of the program, each one of them will represent a specific entity or a concept. To make it easier to understand we can take the example of a person, one block will represent a specific person, and its properties will be the person’s characteristics such as his name, age, genre, height, weight, etc.

In addition to that those objects are not only inanimate and static, they can also perform actions, and have behavior that will be defined by functions or methods associated with the object. Let’s go back to our example of a person, in this case, the person will have methods like walking, talking, eating, etc.

But why is OOP that useful and significant?

Well, as you might have understood through the examples we just gave you, OOP will make programs more manageable and at the same time easier to understand. By organizing the code around those objects and their interactions, this method allows you to break down problems into smaller and more manageable tasks.

Now, let’s see how you can get started with OOP.

Objects and classes

Definition and Role of Objects

Objects are instances of classes. As stated earlier they can be a specific entity or thing that exists in software (person, car, bank account, …). These objects will then encapsulate 2 important parts: data which are its properties and behaviors which are its methods. Data can represent the attributes of the object (age, name, height if it’s a person) and behaviors will represent its actions or the operations that the object will perform (walk, talk, eat, if it’s a person).

These objects are the basis of OOP because they’ll allow you to manipulate real-world entities or abstract concepts within your software.

Introduction to Classes

Classes can be seen as templates used to create objects. They define the common characteristics and behaviors that objects of a particular type will possess. Think of it as a blueprint for a specific type of object. If we take the example of the car the class will specify the attributes a car should have, like the number of wheels the color, the model, and other points. At the same time, it will also define the behaviors or the methods that the object can perform, like accelerate, brake, turn, etc.

To put it simply, the class will encapsulate the common structure and behavior shared by multiple objects.

The Relationship between Classes and Objects

As you might have understood through the explanation, the relationship between those two is that objects are created based on the definitions provides by the classes. Each object created from a class will be unique and have its own set of data and behaviors, but they will all share the structure provided by the class. Just like different cars can be built from the same blueprint.

As a short summary, objects are instances of classes and represent specific entities or concepts in a software system. They encapsulate data and behavior. Classes, on the other hand, are blueprints or templates that define the common characteristics and behaviors shared by objects of a particular type.

Encapsulation and Modularity

Encapsulation Concept

This is another fundamental project in OOP. Encapsulation focuses on hiding data and information within a class. It involved bundling data and methods (remember what those are?) together within the same class and controlling access to them through a well-defined interface. This way the internal workings of an object will be enclosed, providing it with a protective barrier and preventing direct access to its internal data.

The benefits you can get from this are:

• Enhancing security - By restricting access to the internal data, it prevents any unauthorized or unintended modification of it.
• Improving code maintainability - By bundling related data and methods it becomes easier to manage and modify the code
• Allowing abstraction - The internal details of an object are hidden and only the necessary information is exposed

Achieving Modularity

Modularity is the practice of breaking down a complex system into smaller and self-contained modules. OOP supports this practice by definition because of the encapsulation it allows. By doing so, self-contained modules are created that will represent specific functionalities or components of the system.

The encapsulated classes then act as a logical unit allowing the modules to be developed, tested, and maintained independently and making the codebase more manageable. This also enables code reuse since the individual modules can be used in other parts of the app or in another app altogether.

Overall, Encapsulation provides the foundation for modularity by bundling data and behavior within classes and controlling access to them.

Inheritance and Code Reusability

Inheritance Concept

Inheritance is a mechanism that promotes code reuse by allowing a class to inherit data and behaviors from another. It also establishes a hierarchical relationship between the different classes allowing to create new ones based on already existing ones.

When a derived class inherits from a base one, it takes all of its properties and methods. This means that the new class will possess all the characteristics the base one already has, by default, to which you can add additional features, modify existing behavior, or introduce new behavior as needed.

Types of Inheritance and Benefits of Code Reusability

Inheritance can take different forms: single, multiple, and multilevel. Let’s dive into all of them a bit deeper:

• Single inheritance - It involves a class inheriting from a single base class. The derived class will inherit the properties and methods of the base class and then extend or modify them.
• Multiple inheritances - It allows a class to inherit from multiple base classes. The derived class inherits the properties and methods from all the base ones. This method offers a higher degree of code reusability by allowing you to combine features from different classes into a single derived one.
• Multilevel inheritance - It involves a chain of inheritance where a derived class inherits from another derived one. This allows for the creation of a hierarchy of classes, with each level inheriting and extending the features of the previous one.

As you’ve surely understood, through inheritance you can achieve code reusability. So instead of starting from scratch you can extend and modify existing classes to create new ones. Now let’s talk about our final point.

Polymorphism and Flexibility

Polymorphism Concept

This powerful concept lets you treat objects of different classes as being part of a common superclass. This means that you can use the same method name with different implementations depending on the object.

As an example think about a scenario where you have different types of animals and each of them has its unique implementation of the "makeSound()" method. With Polymorphism, you’ll be able to treat all of them as objects of a common superclass named “Animals” as an example. The method will then adapt to each of them without you having to worry about their type.

This promotes flexibility and extensibility in software systems and allows you to write generic algorithms or methods that can work with a variety of object types.

Achieving Flexibility

Using Polymorphism will allow you to achieve 3 main things:

• Code flexibility - By providing a way to interact with objects in a generic manner. This will allow you to write a more generic code, adaptable to many different situations
• Easy extension - If you introduce new subclasses related to the same superclass the existing code will automatically work
• Code reuse and reduction of code complexity - It allows for a unified way to interact with objects of different types, eliminating the need to duplicate code for similar operations

In short, this practice allows for objects from different classes to be treated as all coming from a similar superclass providing you with 3 main advantages that are flexibility, easier extension, and better reuse.

There you go, here is a short but essential introduction to OOP and some of its main principles that are important to understand.

But keep in mind that OOP is a vast and rich topic, and there is much more to explore beyond the basics covered in this blog post. If you liked what you read we encourage you to continue your exploration of advanced OOP concepts, design patterns, and practical #implementation techniques, to make sure you master this practice.

And by embracing these principles, you'll make sure to build scalable, modular, and extensible software systems, easier.

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Duty Team