What are the key differences between object-oriented programming and functional programming, and when would you use one over the other?

Key Differences Between Object-oriented Programming and Functional Programming

Object-oriented programming (OOP) and functional programming (FP) are two popular programming paradigms with distinct differences:

• Core Principle: OOP focuses on representing concepts as objects that have state and behavior, while FP emphasizes on composing functions and avoiding mutable state.
• Data Handling: In OOP, data and behavior are encapsulated in objects, allowing for data hiding and code reuse through inheritance and polymorphism. In FP, data is immutable, and functions operate on this data without side effects.
• State Management: OOP relies on stateful objects that can change over time, while FP promotes working with pure functions that always produce the same output for a given input, thus avoiding state-related bugs.
• Error handling: OOP utilizes exceptions for error handling, whereas FP relies on immutability and monads for handling errors and side effects.

When to Use One over the Other

The choice between OOP and FP depends on the specific requirements and characteristics of the project:

• Use Object-oriented Programming (OOP) when:
• You need to model real-world entities with complex behaviors and interactions.
• You require a flexible and modular design that supports code reusability.
• Your application is stateful and requires managing mutable data and objects.
• Use Functional Programming (FP) when:
• You want to enforce immutability and avoid side effects for better code maintainability.
• You are working with complex data transformations or need to handle data in a declarative manner.
• You aim for a more concise and expressive code that is easier to reason about and test.

Ultimately, the choice between OOP and FP should be based on the project's requirements, team expertise, and the nature of the problem being solved.