OOP vs POP: Difference Between OOP and POP

Programming languages work within specific frameworks, known as programming paradigms, to structure and organize code. These paradigms shape how a program functions and solves problems. Two well-known paradigms are Object-Oriented Programming (OOP) and Procedure-Oriented Programming (POP), each offering a different approach to coding.

To decide on the best approach for any project, it’s helpful to understand the difference between POP and OOP. 

OOP structures code around “objects,” integrating data and functions, while POP emphasizes a sequential, function-based flow. Each paradigm suits different types of projects and brings distinct strengths depending on the project’s requirements and complexity.

In the following sections, we’ll explore the fundamentals of each paradigm and when to use them. 

Origin of Structured Programming

Structured programming emerged in the 1970s, aiming to improve code readability, reliability, and maintainability. It introduced principles that broke down programs into clear, logical blocks rather than relying on complex "go-to" statements. This new approach laid the foundation for modern programming paradigms, which led to the development of Procedure-Oriented Programming (POP) and later, Object-Oriented Programming (OOP).

• Procedure-Oriented Programming (POP):
  • One of the first structured programming methods.
  • Organizes code as a sequence of functions, processing data step-by-step.
  • Effective for straightforward, smaller applications but less flexible for scaling complex software.
• Object-Oriented Programming (OOP):
  • Emerged in the 1980s to address limitations in handling larger, complex applications.
  • Structures code around objects that combine data and functions, promoting modularity and reusability.
  • Improved data encapsulation and abstraction, making OOP ideal for scalable, complex systems.

What is Object-Oriented Programming (OOP)? 

Object-Oriented Programming (OOP) is a way of structuring code by organizing it around "objects" rather than just focusing on functions and steps. In OOP, everything is broken down into objects that represent real-world items, each with its own data and actions. For example, an “Account” object in a banking app could hold balance information and handle deposits or withdrawals.

This approach connects data directly with the functions that work on it, making code more organized, secure, and easy to work with. OOP is especially useful for large, complex projects that may need regular updates or expansions, like mobile apps, simulation systems, and business software. 

Concepts of Object-Oriented Programming (OOP)

Object-Oriented Programming (OOP) is built on core principles that make it powerful for structuring code in a scalable and modular way. Here’s an overview of the four main concepts of OOP, each contributing to robust software design.

1. Abstraction

Abstraction hides the complexity of implementation, allowing the user to interact with the program’s functionality without needing to understand its inner workings.

• Purpose: Simplifies the code interface by exposing only necessary features, enabling users to focus on what a function does rather than how it does it.
• Example: 
  • ATMs allow users to withdraw cash without revealing details about transaction processing, security checks, or bank backend logic.
  • In an e-commerce platform like Flipkart, users can add items to their cart and proceed to checkout without knowing the internal processes of payment authorization or inventory management.

2. Encapsulation

Encapsulation binds data and methods within an object, protecting data integrity and controlling access.

• Purpose: Ensures security and modularity by restricting direct access to data, only allowing interaction through specified methods.
• Example: 
  • In a class BankAccount, private attributes like balance and accountNumber can only be accessed or modified via methods like deposit() and withdraw(). This restriction prevents unintended data modification and maintains integrity.
  • In Paytm’s payment processing system, user-sensitive information (such as account balance and transaction history) is encapsulated within specific classes, ensuring data security and controlled access only through designated methods.

3. Inheritance

Inheritance allows one class (child) to inherit attributes and methods from another (parent), facilitating code reusability and reducing redundancy.

• Purpose: Reuses existing code across related classes, allowing for extensions without rewriting functionality.
• Types:
  • Single: A child class inherits from one parent class.
  • Multi-level: A derived class is created from another derived class, forming a hierarchical chain.
  • Multiple: A class inherits from multiple classes (available in specific languages).
  • Hierarchical: One parent class is inherited by multiple child classes.
• Example: 
  • A class Smartphone could inherit common methods from MobilePhone (such as call() and message()) but add specific features, like browseInternet() or useApps(), that are unique to smartphones.
  • In a system like Tata Motors’ software development for vehicle systems, a Vehicle class could define common properties such as fuelType and engineSpecs, while specific classes like Sedan and SUV add attributes and methods relevant to each type, reusing core vehicle functionality.

4. Polymorphism

Polymorphism enables an object to be treated as multiple types, allowing for dynamic behavior. It supports the same operation with different implementations across various classes.

• Purpose: Increases flexibility by allowing a method to act differently based on the object invoking it.
• Types:
  • Compile-Time (Method Overloading): Multiple methods with the same name but different parameters, allowing flexibility in functionality.
  • Run-Time (Method Overriding): A child class redefines a method from its parent class, enabling customization.
• Example: 
  • A printDetails() method in a class hierarchy might display different outputs depending on whether the object is an Employee, Manager, or Intern.
  • In Swiggy’s delivery management, a DeliveryVehicle class may have a method deliverOrder(), but a BikeDelivery and DroneDelivery class could override it, where each handles delivery differently based on the vehicle type used.

Applications of Object-Oriented Programming (OOP)

Object-Oriented Programming (OOP) is essential in software development, especially for creating modular, maintainable, and scalable systems. Below are some key areas where OOP principles are applied, with its features bringing technical benefits suited to complex project demands.

• Web Applications:
  OOP is important al for developing dynamic and scalable web applications. Frameworks like Django, Flask (Python), and Spring (Java) use OOP to organize components into classes, with each handling distinct functionalities such as user management, data processing, and front-end logic.
  • Benefit: Enables a structured, layered design where components like authentication and data handling are modular, allowing for straightforward updates and efficient troubleshooting.
• Game Development:
  Game engines such as Unity (C#) and Unreal Engine (C++) rely on OOP to define in-game objects (characters, weapons, levels) with properties and behaviors.
  • Benefit: Supports reusability and scalability by organizing different game entities into object hierarchies. This allows game elements to interact seamlessly and provides a clear framework for adding features or expanding game logic.
• Enterprise Software:
  OOP is foundational in enterprise software like Customer Relationship Management (CRM) and Enterprise Resource Planning (ERP) systems, often built using Java or C++. These systems rely on classes to represent business functions (sales, inventory, finance) that interact through well-defined interfaces.
  • Benefit: Ensures modularity, where each business function is independent but can interact securely with others. This reduces redundancy, enhances data security, and enables integration across enterprise functions.
• Mobile Applications:
  In mobile app development (Swift for iOS, Kotlin/Java for Android), OOP helps define classes for screens, UI components, and app data, ensuring organized management of app functionality.
  • Benefit: Promotes consistent behavior across screens and enables efficient updates, as changes to one part of the app don’t disrupt others. This structure is key for managing user sessions and complex UI transitions.
• Simulation and Modeling Software:
  OOP is extensively used in simulation software (e.g., MATLAB, AutoCAD, SolidWorks) to represent entities in fields like engineering and finance. Classes can model physical parts, financial assets, or scientific elements.
  • Benefit: It allows detailed modeling in which each component behaves independently and interacts with others, supporting realistic simulations that are scalable and adjustable.
• Artificial Intelligence (AI) and Machine Learning (ML):
  In ML libraries like TensorFlow and PyTorch, OOP defines components like neural network layers, data pipelines, and training processes. Each element in the ML model is organized as an object with specific roles.
  • Benefit: Supports modular experimentation by allowing easy adjustments to layers or functions. This flexibility accelerates model development, testing, and fine-tuning for improved performance.

What is Procedure-Oriented Programming (POP)?

Procedure-Oriented Programming (POP) is a paradigm that structures code around a sequence of procedures or functions, prioritizing a function-based approach over data encapsulation. POP is built on a linear, sequential model where code is executed step-by-step, and functions are designed to operate on shared global data. In POP, procedures are responsible for performing operations, transforming data, and moving from one task to the next in a top-down manner. Unlike Object-Oriented Programming (OOP), which ties data closely to the methods that manipulate it, POP treats data and functions as independent entities, making it more suitable for simpler, task-focused applications with minimal data interdependency.

Characteristics of Procedure-Oriented Programming (POP)

Procedure-Oriented Programming (POP) is a structured, function-driven programming model that emphasizes modular code design and flexible interfaces. Below are the core principles that make POP effective for organized, modular programming.

• Protocol

In POP, a protocol sets a standard interface that functions or modules adhere to, defining what they should do without specifying how to do it. This approach creates consistent behavior across different parts of the program, even if they’re implemented differently.

• Purpose: Provides a contract that each function or module follows, ensuring predictable interactions.
• Example: 
  • In a data processing application, a protocol could define functions for readData, processData, and writeData, with each module following a consistent interface for data handling.
  • In an e-commerce platform like Flipkart, a protocol could define methods for addItem, processPayment, and generateInvoice in different modules. As long as each module adheres to this interface, they can integrate seamlessly.

• Composition Over Inheritance

POP focuses on composition rather than inheritance, grouping functions by their roles and behaviors instead of creating complex hierarchies. This approach allows modules to adopt various protocols, increasing functionality without rigid dependencies.

• Purpose: Enables modularity, letting functions adopt multiple roles without being confined to a strict hierarchy.
• Example: 
  • A file-processing program may compose different modules such as Encrypt, Compress, and Save, each adhering to their protocols, allowing flexible combinations of functionalities.
  • In a video streaming platform, say Hotstar, modules like Encode, Stream, and Log are composed separately, allowing flexibility in their combination based on the streaming requirements.

• Flexibility and Decoupling

POP promotes loose coupling between components, allowing different modules to interact based on shared protocols rather than direct dependencies. This separation enhances flexibility, making each module independently adaptable and easier to manage.

• Purpose: Allows components to operate together flexibly, based on shared protocols rather than fixed links.
• Example: 
  • In an IoT-based home automation system, sensors for lighting, temperature, and security can operate using protocols for readData and sendData without needing to know about each other, making it easy to add or update devices.
  • In an IoT system, different sensors (temperature, humidity, pressure) follow a protocol for dataCapture and dataTransmit, enabling seamless communication across devices without direct dependence.

• Duck Typing

In POP, duck typing focuses on the behavior of a module rather than its specific type. If a module conforms to a protocol’s expected behavior, it can be used interchangeably with others that also follow the protocol, simplifying the integration of different components.

• Purpose: Focuses on function over form, allowing flexible use of modules based on their behavior.
• Example: 
  • In a multimedia application, modules adhering to a playMedia protocol could handle various formats (audio, video, etc.), dispatching the appropriate method dynamically based on the media type.
  • In a banking system like SBI’s core banking software, any module implementing sendAlert can send notifications (SMS, email, or app notification), irrespective of its underlying implementation, as long as it performs the required action.

• Dynamic Dispatch

POP supports dynamic dispatch, enabling the program to select methods at runtime based on the protocol a function adheres to. This flexibility allows functions to respond differently based on the context, enhancing runtime adaptability.

• Purpose: Provides runtime adaptability, enabling methods to be chosen based on the protocol an object follows.
• Example: 
  • In a multimedia application, modules adhering to a playMedia protocol could handle various formats (audio, video, etc.), dispatching the appropriate method dynamically based on the media type.
  • In Zomato’s food delivery app, modules for deliverOrder could dynamically select methods for bike, car, or drone delivery based on location and order size, ensuring efficient dispatch handling.

Applications of Procedure-Oriented Programming (POP)

Procedure-Oriented Programming (POP) is widely used in systems where a linear, function-driven approach is effective. POP is particularly advantageous in applications requiring predictable task flows, direct hardware interaction, and lower memory overhead. This makes it suitable for smaller programs, embedded systems, and low-level systems programming. Here’s a look at specific areas where POP is highly effective.

• Small Programs:
  POP is efficient for lightweight applications where tasks are straightforward and independent. This structure is ideal for programs with a finite set of operations that can be executed sequentially, as data interactions are minimal and managed through global variables and function calls.
  • Example: In a currency conversion program, each function handles a specific currency calculation. These functions operate independently of one another, without needing encapsulated data structures or object hierarchies, keeping the code clean and manageable.
• Embedded Systems:
  POP’s function-centric approach aligns well with the fixed, resource-constrained environment of embedded systems. Code is organized into dedicated functions that control hardware components directly, making it suitable for real-time control and quick response requirements.
  • Example: In a microcontroller for an air conditioning system, functions are defined for tasks like temperatureCheck(), fanControl(), and compressorStart(). Each function triggers a specific action based on sensor data, allowing for precise control without needing the overhead of object-based design.
• Systems Programming:
  POP is commonly used in systems programming, where code directly manages system resources, device interfaces, and hardware drivers. The function-oriented structure of POP enables a clear flow of tasks and minimizes memory overhead, making it highly suitable for low-level operations.
  • Example: In operating system kernels, POP organizes functions for resource management, such as memory allocation, CPU scheduling, and interrupt handling. Each function operates directly on system resources, enhancing control and efficiency. In device drivers, functions control specific hardware interactions (e.g., reading sensor data, writing to ports), where direct access is crucial.

Suitability of POP vs. OOP 

Each programming paradigm—POP and OOP—serves distinct project requirements based on structure, data handling, and complexity:

• Procedure-Oriented Programming (POP):
  • Best for: Small, resource-constrained applications, real-time embedded systems, systems programming, and hardware control programs.
  • Advantages:
    • Memory Efficiency: Uses minimal memory overhead, an essential factor for embedded systems and low-level programming.
    • Direct Data Access: Functions can manipulate global variables directly, improving response times in systems requiring real-time processing.
    • Sequential Control: Fixed function sequences enhance reliability in scenarios where predictable operation flow is necessary, such as control systems in industrial applications.
• Object-Oriented Programming (OOP):
  • Best for: Complex applications requiring modularity, data encapsulation, and scalability, such as enterprise software, web applications, and data-intensive systems.
  • Advantages:
    • Modular Structure: Encapsulation and inheritance support complex data modeling and flexibility, which makes it easier to extend and maintain large-scale applications.
    • Data Security: Encapsulation protects data integrity, an important feature in systems with high data sensitivity, like financial or medical applications.
    • Reusability and Scalability: Object hierarchies allow for code reusability and easier updates, enhancing scalability in expanding applications.

Key Differences Between POP and OOP

Here's a side-by-side comparison that highlights the core differences between POP and OOP:

Summary of Key Differences

• Structure and Approach: OOP structures programs around objects, each containing its data and functions, following a bottom-up approach that promotes modularity. Conversely, POP uses a top-down approach that breaks programs into sequential functions, focusing on step-by-step execution.
• Data Security and Control: OOP provides data encapsulation, protecting internal data with access modifiers, which enhances security and control. POP uses shared global data across functions, making it efficient but with less data protection.
• Modularity and Reusability: OOP’s modular design supports code reusability, allowing for the creation of flexible, reusable components through inheritance and polymorphism. POP, while efficient in simple tasks, lacks the structural flexibility and reusability provided by OOP’s object hierarchies.
• Examples and Usage: OOP is often used in applications requiring data encapsulation, modularity, and scalability, such as enterprise applications (Java, C++). POP suits simpler, sequential tasks like low-level system programming (C, FORTRAN).

Top Programming Languages Supporting OOP and POP

Programming languages support various paradigms, with some focusing on Object-Oriented Programming (OOP), others on Procedure-Oriented Programming (POP), and many evolving to offer both. Here’s an overview:

OOP-Focused Languages

• Java: Built for OOP with robust support for classes, inheritance, and encapsulation. Ideal for enterprise applications and Android development.
• C++: Combines OOP with low-level memory control, useful in system-level programming, game development, and applications needing both efficiency and modularity.
• Python: Flexible, supporting both OOP and POP; used widely in data science, web development, and machine learning.
• C#: Integral to .NET framework, popular in enterprise software and game development via Unity, with strong OOP support for modular and secure applications.

POP-Focused Languages

• C: Foundational POP language, excelling in structured, efficient code for embedded systems, operating systems, and applications requiring direct memory control.
• Pascal: Structured syntax, widely used in education and systems programming.
• FORTRAN: Dedicated to numerical and scientific computing, optimal for computationally intensive, function-driven tasks in engineering and physics.

Languages Supporting Both OOP vs POP

• Python: Offers both procedural scripting for quick tasks and OOP for modular applications; popular in data science, automation, and web development.
• C++: Allows POP for low-level programming and OOP for modular, reusable code, suitable for games, simulations, and real-time applications.
• JavaScript: Initially procedural, it now includes OOP features and is used widely for web development. It has both modular and functional capabilities.

OOP vs. POP in C++ and Java

In C++ and Java, both paradigms coexist, each suited for different programming needs. Here’s a comparative look:

Transitioning from POP to OOP

Here are some essential guidelines, tips, and concepts to help ease the transition.

Tips for Adopting an Object-Oriented Mindset

• Think in Terms of Objects:
  In OOP, code is structured around objects representing real-world entities, each with specific attributes (data) and behaviors (functions).
• Start with Small OOP Projects:
  Experiment by converting simple POP projects into OOP format, focusing on dividing code into classes and objects to reinforce modular thinking.
• Practice Classes and Inheritance:
  Use classes, inheritance, and encapsulation regularly. Small exercises on creating classes and defining inheritance will help solidify an object-oriented approach.

Key OOP Concepts for POP Programmers

1. Encapsulation:
   Group data and functions within classes, protecting data and restricting external access. This approach contrasts with POP’s global data sharing and offers more controlled, secure data handling.
2. Inheritance:
   Enable code reuse and hierarchy creation by inheriting properties and behaviors from base classes to derived classes. Start with simple inheritance structures to understand how it simplifies and organizes code.
3. Polymorphism:
   Understand how OOP enables functions to take multiple forms, such as through method overloading and overriding. This feature enhances flexibility, allowing different implementations under a unified interface.

Common Challenges in the Transition

• Understanding Encapsulation:
  Moving from POP’s open data sharing to encapsulation can be challenging. Practicing encapsulation through private and public access modifiers can clarify how data hiding increases code reliability.
• Grasping Abstraction:
  Learn to abstract away implementation details, focusing on interfaces and high-level functionality rather than specific logic. Abstraction helps manage complexity by showing only necessary details to users.
• Proper Use of Inheritance:
  Avoid overusing inheritance, as it can complicate design. Where appropriate, stick to a “has-a” rather than an “is-a” relationship to prevent rigid class hierarchies and enhance code flexibility.

Choosing Between OOP vs POP for Projects

When selecting between OOP vs POP, consider project requirements, complexity, and scalability needs:

• Projects Suited for OOP:
  • Large, complex systems like enterprise software, where modularity and reusability are priorities.
  • Scalable applications that will likely expand, such as e-commerce platforms and financial systems.
  • Programs need strong data encapsulation, security, and structured data modeling.
• Projects Suited for POP:
  • Small, straightforward applications where a function-based, linear approach is efficient.
  • Embedded systems and utilities, where low memory and real-time performance are critical.
  • Systems programming or scripting tasks that benefit from procedural, sequential logic.

Boost Your Programming Skills with upGrad’s Software Development Courses

Whether you’re starting out or looking to specialize, upGrad’s courses offer hands-on learning in both Object-Oriented Programming (OOP) and Procedure-Oriented Programming (POP). 

Learn industry-relevant skills and gain practical experience with our expert-led programs.

1. Java Bootcamp
Learn OOP fundamentals with Java, a key language in the tech industry. 

Dive into data structures, advanced techniques, and real-world applications.

2. Full Stack Development Bootcamp
Become a full-stack developer! Master both front-end and back-end programming

Apply OOP and POP concepts to create scalable applications in JavaScript, Python, and more.

3. Free Programming Courses
New to coding? Start with our free courses that cover POP basics and core programming concepts. 

Build a solid foundation without any cost.

Join thousands of learners on upGrad, gain in-demand skills, and get ready for your future in software development.

[Explore Courses on upGrad]

Explore popular articles related to software to enhance your knowledge. Browse the programs below to find your ideal match.

Elevate your expertise with our range of Popular Software Engineering Courses. Browse the programs below to discover your ideal fit.

Enhance your expertise with our Software Development Free Courses. Explore the programs below to find your perfect fit.

Advance your in-demand software development skills with our top programs. Discover the right course for you below.