Functional Programming vs OOP


Procedural programming is the foundation of many popular programming languages, including C, FORTRAN, and Pascall. This method of programming makes use of procedure calls, where each procedure (such as a function or subroutine) consists of a series of to be completed computational stages. It is accessible and simple to comprehend, but as the code grows longer or more sophisticated, changing one function can set off a chain reaction of errors that can be challenging to track down. Computer architects created object-oriented programming (OOP) and functional programming paradigms as alternatives to this spaghetti code.

Each paradigm approaches the way in which code is organized very differently. We’ll describe each programming paradigm in detail and discuss its common applications in this article. By the time it’s over, hopefully, you’ll have begun to form some opinions of your own. Let’s get going!


We’ll discuss:

  1. Functional programming: what is it?
  2. Describe the term “object-oriented programming.”
  3. When to use functional programming versus OOP
  4. Conclusion and next actions


Functional programming: what is it?

Similar to procedural programming, functional programming is focused on creating software made up of functions, albeit there are some minor differences. We will go through some fundamental ideas of functional programming below to emphasize these distinctions.


First-class citizens

We treat functions as primitives. The most basic building blocks of a programming language are primitives. A function can therefore be:

  • stored in a variable
  • passed as an argument
  • returned from a function

Functions are considered to as “first-class citizens” since they possess these skills. In essence, the phrase “first-class citizen” describes a component that facilitates all other publicly available actions.


Pure functions

Writing pure functions wherever possible is one of the principles of functional programming. The number of compiler optimizations made possible by pure functions allows for a large reduction in programme execution time. Pure functions are also the best candidates for unit testing. A pure function can be unit tested independently without concern for where it will be used in the code.

Higher-order functions and recursion

In functional programming, we substitute higher-order functions and tail calls for iterative loop constructs like for and while to create recursive loops. Higher-level enjoyment A function call at the end of a function is referred to as a tail call. If a function calls itself in a tail call, a recursive loop may arise. Recursion is as quick as iterative loops thanks to tail call optimization, also known as tail call elimination, which is performed by many compilers. Recursion is preferred over conventional primitive loops for the following main reasons:

  1. Code simplicity
  2. Refraining from using mutable objects to strengthen code



Functional programming prohibits changing the value that has been assigned to a variable; the only way to modify a value is to establish a new variable. Pure functions can be used in functional programming thanks to immutability. These functions only use the input to produce results; they do not alter it in any way. Functional programming is comparable to arithmetic in this way. Even the Haskell programming language was developed for use in academic computer science environments.

Functional programming, in summary, is a declarative programming paradigm that explains what the programme does without defining the direction of control. It makes use of immutable variables, tail-call recursion, and pure functions. As a result, the code is simpler to comprehend, debug, and unit test. Additional compiler improvements for faster programme execution and less memory usage are made possible by functional programming.


Describe the term “object-oriented programming.”

Object-oriented programming (OOP) is an imperative paradigm in contrast to functional programming. This indicates that the code outlines a step-by-step method for how the program should attain a result. The state of the program is modified procedurally by these statements. Associated functions and their variables are grouped together as objects in object-oriented programming. Variables are referred to as properties and functions are referred to as methods in an object. The object-oriented programming paradigm’s four foundations.  You may frequently be asked to name the four OOP pillars in interviews. Encapsulation, abstraction, inheritance, and polymorphism are the four pillars. As they are all connected, it is crucial to understand these principles when learning object-oriented programming.


  1. Encapsulation: Grouping similar variables and functions into objects is a process known as encapsulation. A class serves as a blueprint or template from which an item is created. Since the variables are included as a component of the object, grouping functions and variables enable functions to be called with little to no parameters.
  2. Abstraction: concealing part of an object’s attributes and operations from external scrutiny. It is ensured that any changes made to the abstracted members of a class in the future won’t affect the rest of the classes by confining specific parameters and functions to an object. Making program expansion and improvement simpler.
  3. Inheritance: An object may take on some of the attributes and operations of another object through inheritance. The Java term extend is used to indicate this inheritance. A superclass or base class is the parent class from which another class extends. The Toyota and Ford classes, for instance, might be expansions of the Car class. Ford Mustang, in contrast, is a development of the Ford-class. In this instance, common code for Ford and Toyota’s superclass cars can be written once. Therefore, inheriting existing properties and methods and incorporating new features into them decreases code duplication and improves code reuse.
  4. Polymorphism: The term “polymorphism,” which literally translates as “many forms,” describes objects that behave differently when performing the same function. The relationships between objects and how members of a superclass are expanded in derived classes are the foundations of polymorphism. Once more, this lessens redundancy and improves reusability. If you’re interested in learning more about polymorphism, we recommend taking the course Learn Object-oriented programming in Java.


Although each OOP pillar is significant on its own, they all depend on one another. Abstraction and inheritance cannot be achieved without encapsulation. In addition, polymorphism requires inheritance to exist. The paradigm is based on each of the four pillars. Objects with independent properties and methods, as well as their interactions with other objects, are the basis for OOP as a whole.


When to utilize functional versus object-oriented programming

Certain programming languages only support one specific paradigm. For instance, Haskell’s inability to allow state mutation makes it by definition a functional programming language. Lisp, F#, and Erlang are further computer languages with a focus on functional programming. Java, C#, and C++ are a few OOP languages or languages that trend more toward the object-oriented paradigm. Many programming languages are multi-paradigm and allow both OOP and functional programming to some extent, including TypeScript and Python. These languages offer some flexibility for developers to use immutable objects and pure functions as they see fit.

One of the most widely used programming languages is Python, which sits in the middle of the object-oriented/functional/mutable spectrum. Immutable types that are built into Python include texts, integers, and Booleans, to mention a few. But in Python, custom classes are often mutable data. What programming paradigm is used most frequently with a language like Python is mostly up to the programmer.

Most developers currently choose OOP as their preferred paradigm, mostly because of its accessibility. The server side of apps, data manipulation, and web crawl all benefit greatly from functional programming. For instance, Haskell functional programming was used to create Facebook’s whole spam filtering system. Most of the time, it’s difficult to say with certainty which paradigm will benefit you the most in your education and job as a software developer. Good software engineers employ methods and practices that apply to both functional and object-oriented programming.

It can be advantageous for you to add some functional programming limitations even if you primarily program in an OOP environment. You could discover that your code is clearer and simpler to debug as a result. Repetitive code is one of the largest obstacles to creating an effective, user-friendly API, so learning and using functional programming concepts now could be beneficial in the future.

Making a roadmap for potential future changes to the program can be helpful when choosing what paradigm to build a new program in. An object-oriented approach makes the most sense if your program has to conduct a certain amount of operations on entities and you plan to expand the application by adding new entities. Functional programming will be less problematic during scaling if, instead, you want to add more processes while maintaining a fixed number of entities.


Conclusion and next actions

Functional programming, at its most basic, employs immutable data to instruct the program on exactly what to do. Through objects changing the program’s state, object-oriented programming instructs the computer on how to attain results. Elegant code can be produced using any paradigm. From an OOP standpoint, you might be modeling something after the real world using clay. It more closely mimics putting building pieces together in functional programming to eventually produce a unified product.