Object vs Class in OOP: Explained with Code

Let us explore this idea with relatable examples and easy-to-understand code snippets.

By the end of this article, you will not only understand what classes and objects are but also how to use them in code. Whether you are a beginner or someone brushing up on OOP concepts, this guide will help you build a strong foundation.

What is Object Oriented Programming?

Before jumping into classes and objects, let us quickly touch on what Object Oriented Programming is.

OOP is a programming paradigm that organizes software design around data or objects, rather than functions and logic. Each object can hold data in the form of fields or attributes and code in the form of methods or functions. OOP promotes concepts like encapsulation, inheritance, polymorphism, and abstraction, making it easier to build maintainable and scalable software.

What is a Class?

A class is a user-defined data type. Think of it as a blueprint or a template. It defines what attributes (data) and behaviors (methods) an object of that class will have.

For example, if you were to create a program related to animals, you could define a class called Animal. This class could include attributes like name, color, and number of legs, and methods like make_sound() or eat().

Example in Python

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class Animal:

    def __init__(self, name, color):

        self.name = name

        self.color = color



    def make_sound(self):

        print(f"{self.name} makes a sound.")



    def eat(self):

        print(f"{self.name} is eating.")

Here, Animal is a class. It defines two attributes (name and color) and two methods (make_sound() and eat()).

But this code does not do anything on its own until we create objects from it. That is where objects come in.

What is an Object?

An object is an instance of a class. It is like building a house based on a blueprint. You can build many houses (objects) from the same blueprint (class), and each house can have different colors or features.

Let us use the same Animal class to create an object:

python

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dog = Animal("Dog", "Brown")

cat = Animal("Cat", "Black")



dog.make_sound()

cat.eat()

Here, dog and cat are objects created from the Animal class. Each object has its own values for the attributes, and you can call their respective methods.

When you run this code, the output will be:

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Dog makes a sound.

Cat is eating.

So in simple terms:

• A class defines the structure and behavior.
   
• An object is a real-world instance of the class with actual data.

Key Differences Between Class and Object

Let us now break down the core differences between a class and an object.

Real Life Analogy

Imagine a class called Car. It defines the common properties and behaviors of all cars — like start_engine, accelerate, brake, and properties like color, brand, and speed.

Now, you go to a car showroom and buy a red Honda. That red Honda is an object of the class Car. You can start it, accelerate it, and brake it. Similarly, someone else might buy a blue Toyota. That is another object of the same class but with different values for its attributes.

So, while the Car class tells you what a car can do, the actual car you drive is the object that does those things.

More Code Examples: Java Edition

Let us look at how classes and objects work in Java, one of the most popular OOP languages.

Java Class Example

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public class Student {

    String name;

    int age;



    void study() {

        System.out.println(name + " is studying.");

    }

}

Creating Objects in Java

java

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public class Main {

    public static void main(String[] args) {

        Student student1 = new Student();

        student1.name = "Suhani";

        student1.age = 20;

        student1.study();



        Student student2 = new Student();

        student2.name = "Ravi";

        student2.age = 22;

        student2.study();

    }

}

Output

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Suhani is studying.

Ravi is studying.

In this Java example, Student is the class. student1 and student2 are objects of the Student class. Each one has its own name and age, and can perform the study() method.

When to Use Classes and Objects

If your application involves entities that share common properties and behaviors, it is a good idea to define them as classes and then create multiple objects.

For example:

• If you are building a school management system, you will create classes like Student, Teacher, Classroom, and Course.
   
• If you are creating a game, you might define classes like Player, Enemy, Weapon, and Level.
   

Each of these classes can be used to create several objects representing real-world entities within your software.

Common Misconceptions

“Can I write code without using classes and objects?”

Yes, you can, especially in languages that are not strictly object oriented like C or procedural Python. But as your project grows in complexity, using OOP concepts like classes and objects makes your code much more organized and reusable.

“Is an object always created manually?”

Not always. In many real applications, objects are created dynamically based on user input or data from a database. For example, in an e-commerce application, every product you view is an object created dynamically from a Product class.

“Can an object exist without a class?”

In pure OOP languages, the answer is no. An object always needs a class to define its structure and behavior.

Benefits of Using Classes and Objects

• Reusability: Once a class is created, it can be reused to make multiple objects.
   
• Scalability: It becomes easier to scale your project by creating more objects without rewriting code.
   
• Maintainability: If you need to change how something works, you can simply update the class and all related objects will follow the changes.
   
• Real world modeling: Objects represent real-world entities, making it easier to relate code with reality.

OOP in Practice: Industry Relevance

Most modern software applications, from web apps to mobile games, are built using OOP. Languages like Python, Java, C++, and JavaScript all support object oriented concepts.

If you are planning a career in software development, data science, app development, or backend engineering, understanding OOP is absolutely essential.

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If you are serious about mastering programming, then you should check out the Object Oriented Programming in Python and Java Course by Uncodemy. It is designed for beginners and walks you through classes, objects, inheritance, polymorphism, and much more with hands-on coding and real-world projects.

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Final Thoughts

The difference between classes and objects is foundational in programming, especially in OOP. A class is the idea, the design, the mold — while an object is the result, the real-world version, the item you can use.

Whether you are creating a school app or a complex inventory system, you will likely start with classes and build everything else around objects. Knowing how to structure and use them effectively will take your coding skills to the next level.

So, the next time someone asks you “What is the difference between a class and an object?”, not only will you know the answer — you will be able to show it with confidence and code.