What is Object Oriented Programming? 10 Key Concepts with Examples

• By Smith Joe
• 20-06-2025
• Software

Have you ever asked yourself how software systems can carry out complex tasks efficiently? In the era of software development, understanding object-oriented programming (OOP) is highly important. It is the secret behind developing scalable, maintainable, and reusable software.

According to the Stack Overflow survey, nearly 70 per cent of coders employ object-oriented programming in their work. OOP enables programmers to divide issues into smaller, manageable objects, which may be representatives of real-world objects. Such objects may include both data (attributes) and behaviour (methods), allowing code to be more modular and easier to comprehend.

In this article, we will explore the 10 key concepts of Object-Oriented Programming, accompanied by relevant examples. It will provide you with a clear understanding of the basic programming paradigms, including inheritance, and conclude with polymorphism and encapsulation.

What is Object Oriented Programming?

The Code Institute defines the concept of Object-Oriented Programming as a programming paradigm where a programmer considers classes and objects to represent real-world entities in software development, encompassing inheritance, encapsulation, and polymorphism.

Every object denotes something in the real or abstract world, such as a car, a person, or a bank account.

Such objects have:

• Attributes: Features or properties (ex, the colour of a car, the age of a person).
• Methods: Actions or behaviours they may do (e.g., a car can drive, a person can speak).

Rather than having to write code that executes linearly, OOP permits you to create these objects and specify their interaction with one another. This simplifies the management and scaling of software since one can make changes to single objects without tampering with the whole system.

What is the Concept of OOP?

A query arose in the minds of people about what object-oriented programming is, and several key concepts that help structure and organise code effectively. OOP is a rapidly developing trend, and a significant number of students gain admission to this field to learn this skill.

However, even the most brilliant students often struggle with the immense workload when it comes to writing long projects, such as theses. That’s where first-class dissertation writing services from The Academic Papers UK come in. They provide comprehensive academic support to help students balance their studies with their technical aspirations.

Let's now discuss these 10 object-oriented programming concepts in detail.

1. Classes and Objects

Classes are templates in Object-Oriented Programming (OOP) that enable you to create objects. They specify the attributes and the methods that the objects of that class will possess. For example, ‘A Car' class may declare attributes such as colour and model, and methods such as drive.

When a specific car object is created, it will have its unique values for colour and model, but can perform the drive method. According to research by Booch, classes and objects make it too simple to encode real-world objects and increase understandability and reusability.

2. Encapsulation

Encapsulation is an Object-Oriented Programming concept that combines data and methods into a single class, limiting access to certain parts of it to prevent misuse. It also enables developers to regulate access or modification of data through access modifiers such as private, protected and public.

This is intended to prevent the internal state of an object from being vulnerable to unwarranted alteration by external entities, which implies high security and minimal occurrence of faults. Research Gate report indicates that encapsulation is a means of simplifying systems by concealing their implementations and revealing only the required services to the external world.

3. Abstraction

Often, a query arises in the mind about what the object-oriented programming concept of Abstraction is. Abstraction is the process of simplifying complicated systems by concealing irrelevant details and highlighting only the relevant features to the user. This enables the developers to work with objects at a higher, more natural level.

For example, a user operates a car’s steering wheel without needing to know how the steering mechanism works. Abstraction can help create systems that are easier to maintain and have fewer errors by focusing on relevant features. The CMU School of Computer Sciences emphasises thevalue of abstraction in system design, as it enables developers to cope with complexity byabstracting out various levels of functionality.

4. Inheritance

Inheritance, an object-oriented programming concept, enables a new class to inherit the features and behaviours of an existing one. It enhances the reusability of code and provides a hierarchy relationship amongst classes.

For instance, a Dog class can be derived from a Mammal class, and it inherits attributes such as fur and methods like breath, while also defining its methods, such as bark. This kind of relationship enables the code to be reused and the system to be easier to extend.
The critical analysis of Central Lancashire reveals that inheritance produces cleaner code because it reduces redundancy and encourages the extension of functionality.

5. Polymorphism

The most frequently asked question about the concept of Polymorphism in Object-Oriented Programming is related to the idea of Polymorphism Itself. In OOP, it enables the treatment of objects of dissimilar classes as objects of a shared superclass. This is implemented as follows: a method may behave differently based on the object it is acting upon.

By way of illustration, a makeSound method might act in different ways when called on an instance of the classes Dog (barking) and Cat (meowing). Research by Stroustrup found that polymorphism improves flexibility and enables systems to be more adaptable to change without making changes to existing code, which is essential to developing scalable applications.

6. Composition

The Composition Object-Oriented Programming concept is a design rule where a reference to objects of another class is contained within another class, and the relationship is one of containment, specifically a ‘has a or ‘is a relationship. This enables complex objects to be constructed from simpler ones.

For example, a class of Car contains an object of Wheel, Engine, and Seat. This enhances modularity and the organisation of code. The Victoria University of Wellington’s research highlighted that composition is one of the main principles of designing flexible systems where objects can be constructed out of other objects to build more complicated structures, and each object has the sole responsibility.

7. Association

Association is used to describe the connection between two distinct classes through objects. The relationship may be one-to-one, one-to-many or many-to-many, based on the behaviour of the objects.

For Instance, a Student class may have an association with a Course class, where a student may take multiple courses, and a course may have multiple students. Association was studied as a basic relationship in object modelling. In the Visual paradigm study, it was essential to enable the modelling of flexible systems in which entities may semantically interact with each other.

8. Aggregation

Aggregation is a special type of object-oriented programming concept. Aggregation is a kind of association that expresses a whole-part relationship, but with a weaker connected lifecycle. For Example, A University may contain many Department objects, but the destruction of the university object does not eliminate the department objects, which can exist independently.

The aggregation enables greater freedom in structure over composition, where the lifecycle of the objects contained is closely matched to that of the parent object. Studies by Coad & Yourdon have emphasised the technique of aggregation to model systems in which the components may exist independently of the whole, and which can therefore scale and adapt better.

9. Dependency

Dependency means that one class cannot properly work without the other. For example, when classes 1,2, and 3 depend on the super class to meet their needs. The relationship among classes maintains a hierarchical structure. This is a very important relationship when it comes to creating flexible and maintainable code, as one class can influence dependent classes when it is changed.

Another example is that the car class may require the Engine to operate. The dependency is commonly implemented using interfaces or dependency injection, which encourages loose coupling of classes. As the ScienceDirect journal report observes, dependencies should bereduced as much as possible, as this improves modularity and facilitates the maintenance and testing of systems.

SomeClass interacts with SuperType, while Class1, Class2, and Class3 depend on the SuperType interface, establishing a hierarchy to meet their need. A hierarchical relationship has been shown in the given figure.

Image source: Stack Exchange software engineering

10. Overloading

The fact that a class can contain multiple methods with the same name but different parameters is called method overloading. This enables the reuse of the same method to perform various tasks depending on the input provided.

For instance, the add method may add two integers, two doubles or even two strings. Overloading also makes the code more intuitive and simpler because it is possible to include similar operations under the same method name.

Research conducted by Stroustruphas shown that overloading helps produce cleaner and more readable code,as it eliminates the need for multiple method names to perform a similar operation.

Advantages of OOP

After understanding the most frequently asked query, ‘What is object-oriented programming?', we will now discuss some benefits of OOP, which are mentioned below:

1. Modularity

Object-oriented programming concepts encourage modularity, breaking a program into autonomous objects. It also enables developers to work on particular pieces of the application. Therefore, it is simpler to debug and test specific elements without affecting the entire application.

Modularity improves cooperation, as different developers can work on other modules anyway. Booch says that the modularity concept results in cleaner and more organised code and less complexity.

2. Reusability

Another benefit of Object-Oriented Programming concepts is reusability, which helps to reuse the existing classes in various components of an application or even in a separate project. This is done by inheritance and composition. After defining a class, it is very easy to extend or reuse it, which saves time and resources. Code reuse also eliminates redundancy and helps to foster consistency in large systems.

3. Scalability

OOP supports scalability, which facilitates the process of enlarging a system. The developers can introduce new classes and objects to meet changing needs without interfering with the existing code. Consequently, the system will be more flexible for expansion.

As the University of Twente reported, the Scalability of OOP makes it easy to modify and extend, ensuring that software can be expanded as the needs of users change.

4. Maintainability

The encapsulation and abstraction of OOP result in increased code efficiency. Because the complexity of the internal logic is concealed, developers can work at a high level of abstraction, and the probability of introducing errors during updates is decreased.

This simplified form of maintenance means that the effect of bugs in a certain section of the system does not spread to the rest of the program. A proper encapsulation also eases the software debugging and upgrading.

5. Flexibility

While discussing the Object-Oriented Programming concept of flexibility, Polymorphism is a very powerful feature that brings a great deal of flexibility, allowing objects to be treated as instances of the parent class. This allows writing more generic and flexible code.

Polymorphism promotes code reusability and enables systems to be easily expanded with minimal modifications. According to the ResearchGatereport, flexibility enables developers to expressdiverse behaviours without altering the existing codebase, which is highly beneficial incomplex systems.

6. Security

OOP provides security by hiding the internal state of an object, which limits access to it. OOP helps in protecting data integrity by revealing only the required data through techniques. This design concept helps to prevent unwanted alteration of data, ensuring that sensitive information is kept safe. The reportindicates that encapsulation minimises the chances of accidental or malevolent manipulation of the state of an object.

7. Real-World Modelling

The structure of OOP reflects the interactions in the real world, and therefore, developers find it easier to model complex systems using the OOP structure. Entities are modelled as objects, and interactions between them are projected onto methods.

This corresponds to the actual system and enhances the developer’s perception, making the design more intuitive. OOP enables developers to think about solutions that are more akin to our concept of the real world, making the programming process more natural and easier to comprehend.

Is Python an OOP?

After discussing the most debated query, what is object-oriented programming? Now, we will explore the concept of Python about Object-Oriented Programming.

Yes, Python is an object-oriented programming language. It is undoubtedly OOP at its roots, although it also supports procedural and functional programming.

Key OOP Features in Python:

• Classes and Objects: Python provides all OOP features through classes and objects.
• Encapsulation: It provides a means for containing information and protecting the integrity of the object (through name conventions) via information hiding and member protection (private and public naming).
• Inheritance: Python allows a class to inherit properties and behaviours from an ancestor class.
• Polymorphism: Functions and methods can vary based on input, and a class can override a method of a parent class.

Why Python is Unique in OOP:

• Python deals with everything as an object, including functions and classes themselves.
• It uses dynamic typing and duck typing, increasing flexibility in OOP design.

In summary, Python is fully equipped to support OOP principles while also giving developers the freedom to use other paradigms when needed.

What are real-life examples of OOP?

A Deep Understanding of the query requires a real-life example of object-oriented programming, which helps to grasp the concept of OOP. Here are some real-life examples of OPP given below.

• Car as an Object

In OOP, a car can be a class. Each car object has certain attributes such as colour, model and speed, and several methods such as start, stop and accelerate. You can create many objects with the same class (let's say a car); however, each object will have different properties. That’s encapsulation and abstraction interacting with the car without having any idea what’s inside. You can define a class ElectricCar that is a subclass of Car, demonstrating inheritance and polymorphism, two of the main OOP concepts that reflect how different kinds of cars reuse and adapt behaviour.

• Bank Account

A bank account is a wonderful real-world example of the Object-Oriented Programming concept. It could be a class with attributes such as account number, holder name, and balance. Deposit, withdraw, and check balance represent the things a person can do.
Account types (savings/checking) can be derived from the base Account class, and they can override or augment their behaviour. This represents encapsulation (data hiding), inheritance (common structure), and polymorphism (differing method behaviours).

• Smartphone

A smartphone is an entity with attributes such as brand, model, and operating system (OS). call, text, and takePhoto are methods. You would define a phone base class, and then derive AndroidPhone and iPhone from it.

Each derived class can provide its implementation of how installApp is supposed to work (that’s polymorphism). An object is a combination of data and behaviour; it represents encapsulation. A user can interact with the object through a simple interface, without needing to be aware of its complex internal workings. This is what abstraction is all about.

• Employee Management System

In the system of a company, every employee is an object. The following are potential attributes of an Employee class, such as name, ID, title, or salary. Functions could be called calculateSalary or promote.

Descendants such as Manager or Developer can extend the Employee class and override its calculateSalary method, demonstrating polymorphism. This is highly scalable and reusable, adding a new role just means creating a new subclass. The system encapsulates employee data and behaviour into objects, thus demonstrating the OOP concept of real-world objects.

• Library System

For comparison, see a library example of the Object-Oriented Programming concept, well-written in TypeScript. Books, members and staff are classes. A class Book has a title, author, and ISBN. It might have methods borrow or returnBook. A Member class might have methods like borrowBook or payFine.

This game is played with these items, which represent a physical library. Inheritance enables similar types of members (students, faculty) to reuse the code. Encapsulation hides internal details from users. This modularisation makes it easy to control the complexity and improve the maintainability and scalability of the software

What Is Object-Oriented Programming?

Object-oriented programming refers to the object of a class instance where code is currently executed. It is, in most cases, used to indicate the difference between a class attribute and a parameter if they have the same name.

For instance, you do this in a class method. name = name; sets the value of name to the translation name attribute. “This" can be convenient in reading instance variables, invoking other methods in the class, or returning the object. It makes the code point to the current object and doesn't confuse things when working with large classes.

What Are The 4 Basics of OOP?

There are four fundamental principles of object-oriented programming: Encapsulation, Abstraction, Inheritance, and Polymorphism.

1. Encapsulation is the practice of hiding internal data and instead providing a method to access it.
2. Abstraction simplifies the problem by creating a model of the appropriate classes.
3. Inheritance is the ability that classes in programming have to inherit from other classes; In other words, use a class as not only a base of the other but also, in simple words, to directly take some properties and behaviours of a class and use them in the new one.
4. Polymorphism takes advantage of the fact that objects can be used as if they belong to their parent class, rather than their instantiated type, and thus behave correctly in different uses of the same method.

The four principles assist programmers in developing flexible, scalable, and maintainable software by keeping the code reusable and understandable, and should lead to clearer and better-organised programs.

What is Object Oriented Programming with a Simple Example?

OOP is a programming style that has a great deal to do with the way programs are constructed using objects. Each object corresponds to a real-world entity with data (attributes) and behaviour (methods).

For example, you have a class Car that has attributes colour and speed, can drive and can brake. You can then create different car objects like car1 and car2 with their colour and speed, but with the same method. It also structures code in a way that is easier to comprehend and maintain by breaking it up into reusable pieces. It’s as if you are building programs by connecting building blocks, with each one knowing how to behave.

What Is An OOP Example in Real life?

Here is a real-world demonstration of OOP for you: Let’s take a smartphone app, such as a messaging app. In this type of app, you have a User class with attributes such as username, status and methods such as sendMessage(), updateStatus(). You can create multiple users (objects) from the class, each having its own data but using the same actions.

It could also be using inheritance, where AdminUser inherits from User but has some more rights. This is an analogy to how in the real world you (Users) send (Messages), and receive or store them (Settings), so the whole thing is just easier to build, update, and maintain using OOP.

How Would You Explain OOP to a 6-Year-Old?

Suppose you have a box that contains toy animals. They are all different toys: a lion, a dog, and a cat, but they are all animals. Every toy makes noises: roar, bark, meow.

In object-oriented programming, we create small “plans” that we call classes, such as a “ToyAnimal” class. We then produce real toys, which we call objects, under that plan. Each toy (object) can have its specific colour or sound, but they all come from the same concept.
So, OOP is like playing with a toy that knows about itself and knows that it’s a toy, based on the way you’ve designed it.

What Are the Differences Between C and C++?

C and C++ are programming languages that differ slightly in their features and capabilities. C, in a nutshell, is a procedural language that is all about function calls and the order of operations. It does not include object-oriented ideas such as classes or objects. C++ is a superset of C, containing everything in C, and is also an object-oriented programming language.

This says you can write classes and objects and make use of concepts like inheritance or polymorphism in C++. C is excellent for low-level system programming, but C++ is ideal for more complex software such as games or applications. C++ is more systemic and structured, so projects are more easily maintainable in larger sizes.

Conclusion

In a nutshell, the Object-Oriented Programming concept is a strong pattern that provides a structure to your software based on data, or objects, rather than actions. Object-oriented programming encourages code reuse by adopting the principles of encapsulation, inheritance, polymorphism, and abstraction. We have explained 10 OOP concepts with real-world examples; these ideas demonstrate how to address the most complex problems in computer programming using optimised code.

Learning OOP is extremely useful. It becomes difficult for students to manage the college workload when they learn this skill, especially when they need to work on their dissertations. Even intelligent students face difficulties managing this workload. If you are facing a similar situation, consider contacting London-based dissertation writing platforms that employ experts. With a team of professionals, you can comprehensively deal with academic challenges with ease and focus on honing your learning skills, ultimately paving the way for your success.