Introduction to OOP

Object-Oriented Programming (OOP) is a programming paradigm that organizes code into objects. We have used the term object in the C++ language to mean a piece of memory that is used to store values. As you already know, an object with a name is called a variable. However, in OOP, the term object has a slightly different meaning. OOP focuses on modeling real-world entities and their interactions, making it easier to design, implement, and maintain complex software systems. This section provides an overview of OOP and its key concepts.

Procedural programming

Before diving into the concepts of OOP, let's briefly discuss procedural programming. In procedural programming, a program is a set of instructions (procedures) for a computer. These instructions define how to manipulate data and perform actions using statements and functions. Variables and functions that operate on the data are separate entities, and programmers combine them to achieve the desired outcome.

Procedural programming often lacks an intuitive representation of real-world entities, as programmers need to manage and connect the properties (variables) of things with their corresponding behavior (functions) manually.

Let's imagine that you are building a house.

In a procedural approach, you would create a set of instructions or "procedures" for each step of the construction. You start by preparing the site, then excavate the foundation, pour the concrete, build the walls, and the roof, install utilities, and so on. Each of these steps could be a function in procedural programming, for example:

prepareSite();
digFoundation();
pourFoundation();
buildWalls();
installRoof();
installUtilities();

In this approach, each function performs its tasks separately and in a certain order. But what if you want to change the order? Or you want to build a house with different characteristics—for example, with an attic or a basement? You would have to rewrite functions or add new ones, which can lead to complexity and repetitiveness in the code.

Object-oriented programming

Now let's imagine an object-oriented approach. Instead of separate functions, you would create objects that represent different parts of the house and have their own properties and methods. For example: a door or a window, each with its own characteristics and abilities, like color or opening and closing. These objects are created from a class, which acts like a blueprint. This blueprint outlines the general details and capabilities that each object of that class should have.

Look around. There are objects everywhere: books, buildings, food, and even yourself. Objects have two main components:

• properties, for example: weight, color, size, shape, etc.;
• behavior they may exhibit, such as opening something, doing something, etc.

Properties and behavior are inseparable from each other. So, OOP provides the ability to combine properties and behavior into an independent union—an object that can then be reused.

For our previous example, you could have an object "Foundation" that has properties such as "depth", "material", and methods such as "dig", and "pour". Similarly, you could have an object "Wall" with methods "build", "paint", and so on.

class Foundation {
public:
    int depth;
    string material;
    void dig();
    void pour();
};

class Wall {
public:
    int height;
    string material;
    void build();
    void paint();
};

So instead of following a strict set of procedures, you can manipulate these objects, change their properties, and call their methods as needed.

This allows us to structure programs in a modular way, which not only facilitates writing and understanding code but also enables a higher level of code reuse. Objects also provide a more intuitive way of working with data, allowing the programmer to define how they will interact with objects and how these objects will interact with others.

It is important to understand that OOP doesn't replace traditional programming methods. It is an additional tool for managing complexity.

Basic concepts in OOP

Object-oriented programming consists of many additional useful concepts:

• Encapsulation means grouping related data and functions into a single unit called an object. An object can hide its internal details and provide only specific ways to interact with it. This helps protect data from being misused and makes it easier to change the internal implementation without affecting other parts of the program.
• Inheritance allows the creation of new classes that inherit properties and functionality from existing classes.
• Abstraction means representing complex systems or ideas in a simpler and more understandable form. You highlight only the most important details and hide everything else.
• Polymorphism means using the same code to work with different types of data or objects. It means that you can call the same function, but it will behave differently depending on the type of data or object it works with. This allows us to write more flexible and versatile code that can work with various data or objects without the need to write separate code for each of them.

You will explore each of these concepts in their respective topics. But here are real examples that will help you understand these concepts a little more, even now:

• Encapsulation: Think of a capsule pill. Inside the capsule, there are different types of medicine mixed together, but you don't need to know exactly what they are or how they are mixed. You just need to know that the capsule can relieve your headache. Similarly, in programming, an object encapsulates data and functions into a single unit.
• Inheritance: Consider a family tree. Children inherit characteristics from their parents. They might inherit their parents' eye color, hair color, height, and so on, but they can also have unique characteristics of their own. Similarly, in programming, a new class can inherit properties and methods from a parent class, while also having its own unique properties and methods.
• Abstraction: Imagine you are driving a car. To drive, you just need to know how to operate the steering wheel, pedals, and switches. You don't need to understand the complexities of how the engine, transmission, or braking systems work. This is similar to abstraction in programming, where complex details are hidden, and only the essential features are provided for use.
• Polymorphism: Think of a mobile phone. It can be an iPhone, a Samsung, a Huawei, or another one. They all have a common method of operation (like making calls, sending texts, browsing the internet), but the way they perform these operations can be different. This is similar to polymorphism in programming, where the same function or method can behave differently depending on the type of object or data it's working with.

OOP, like any programming paradigm, has its strengths and weaknesses. It's like switching from riding a bicycle to a motorcycle. Once you understand and start using OOP, you might not want to go back to procedural programming, especially for solving large and complex problems. However, it's also important to understand that not every problem requires an OOP approach, and sometimes a procedural or a different approach might be more suitable.

Advantages of OOP

Code Reusability: OOP promotes code reusability through the concept of inheritance.

• Modularity: OOP encourages the creation of modular code by organizing functionality into classes and objects. Modules can be developed independently, tested separately, and easily integrated into larger systems, enhancing maintainability and scalability.
• Maintainability: OOP facilitates code maintenance and updates. With encapsulation, changes made to one part of the codebase do not affect other parts, as long as the external interface remains unchanged. This reduces the risk of introducing bugs and makes maintenance tasks more manageable.
• Flexibility and extensibility: OOP allows for easy extension of existing code. Through inheritance and polymorphism, new classes can be created that inherit properties and behaviors from existing classes, enabling developers to add new features without modifying the original code.
• Abstraction: OOP supports the concept of abstraction, where complex systems can be represented by simplified models.

Disadvantages of OOP

• Learning curve: OOP can have a steeper learning curve compared to procedural programming. Understanding concepts such as classes, objects, and inheritance requires a shift in thinking and may require additional time and effort to grasp fully.
• Increased complexity: OOP introduces additional layers of complexity due to the need for class hierarchies, relationships, and object interactions.
• Performance overhead: OOP can introduce performance overhead compared to procedural programming. The additional layers of abstraction and encapsulation can result in slower execution times and increased memory usage.
• Design constraints: OOP imposes certain design constraints, such as the need to define class hierarchies and relationships upfront.
• Debugging complexity: Debugging OOP code can be more challenging compared to procedural code. With multiple interacting objects and complex relationships, identifying the source of a bug or error can be more time-consuming and require advanced debugging techniques.

Conclusion

In conclusion, Object-Oriented Programming (OOP) is a paradigm that offers numerous benefits for software development. By organizing code into objects and classes, OOP promotes modularity, reusability, and maintainability. Key concepts like inheritance, polymorphism, and encapsulation enable developers to create flexible and extensible software systems.

OOP focuses on modeling real-world entities and their interactions, making it easier to design, implement, and maintain complex software systems.