Aditya Gupta
"Most commonly asked question by interviewers"

"Most commonly asked question by interviewers"

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Aditya Gupta
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2 min read

Hello everyone!

As we prepare for technical interviews, it's crucial to understand the four pillars of Object-Oriented Programming (OOP), as these concepts are frequently asked by interviewers. Here’s a brief overview and some key points you can use in your responses:

1. Encapsulation

Definition: Encapsulation is the bundling of data (attributes) and methods (functions) that operate on the data into a single unit, or class. It restricts direct access to some of the object's components and can prevent the accidental modification of data.

Key Points:

  • Achieved through access modifiers (public, private, protected).

  • Promotes data hiding and abstraction.

  • Example: Use getters and setters to control access to an object's properties.

2. Abstraction

Definition: Abstraction is the concept of hiding complex implementation details and showing only the essential features of an object. It simplifies the interface and reduces complexity.

Key Points:

  • Can be achieved using abstract classes and interfaces.

  • Allows the user to interact with the object without needing to understand the intricate details.

  • Example: A car’s interface (steering wheel, pedals) abstracts away the complexity of the engine and mechanics.

3. Inheritance

Definition: Inheritance is a mechanism where a new class (child class) derives properties and behavior (methods) from an existing class (parent class). This promotes code reusability and establishes a relationship between classes.

Key Points:

  • Supports the concept of "is-a" relationship.

  • Can be single, multiple, or multi-level inheritance, depending on the language.

  • Example: A Dog class can inherit from an Animal class, inheriting properties like species and methods like eat().

4. Polymorphism

Definition: Polymorphism allows methods to do different things based on the object it is acting upon, even when they share the same name. It can be achieved through method overriding and method overloading.

Key Points:

  • Supports method overriding (runtime polymorphism) and method overloading (compile-time polymorphism).

  • Enhances flexibility and extensibility of code.

  • Example: A draw() method that behaves differently based on whether it is invoked on a Circle or a Rectangle object.

Feel free to ask questions or share your thoughts on these concepts! Good luck with your interview preparations!

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