Lecture 129:-   Abstraction In C++

Abstraction is a fundamental concept in object-oriented programming (OOP) that allows you to hide complex implementation details while exposing only the essential features of an object. It provides a way to model real-world entities in a simplified manner, allowing you to focus on what an object does rather than how it does it. In C++, abstraction is achieved through the use of abstract classes and pure virtual functions.

Here's how abstraction is implemented in C++:

Abstract Classes: An abstract class is a class that cannot be instantiated directly and is meant to serve as a blueprint for other classes. It contains one or more pure virtual functions, which are virtual functions without a concrete implementation in the base class. Abstract classes define an interface that derived classes must implement.

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class Shape { public: virtual float area() const = 0; // Pure virtual function virtual float perimeter() const = 0; // Another pure virtual function }; class Circle : public Shape { private: float radius; public: Circle(float r) : radius(r) {} float area() const override { return 3.14 * radius * radius; } float perimeter() const override { return 2 * 3.14 * radius; } }; int main() { // Shape shape; // Error, cannot create an instance of an abstract class Circle circle(5); std::cout << "Area: " << circle.area() << std::endl; std::cout << "Perimeter: " << circle.perimeter() << std::endl; return 0; }

In the above example, the Shape class is an abstract class with two pure virtual functions area() and perimeter(). The Circle class is derived from Shape and provides concrete implementations for the pure virtual functions.

Abstraction allows you to create a common interface for different classes, promoting code reusability and helping you manage complexity.

Benefits of Abstraction:

1. Simplification: Abstraction simplifies complex systems by focusing on essential features and ignoring irrelevant details.
2. Encapsulation: Abstraction enforces encapsulation, allowing you to hide internal implementation details.
3. Modularity: Abstract classes provide a clear separation of concerns, making your code modular and easier to maintain.
4. Polymorphism: Abstraction allows you to work with objects of different classes through a common interface, promoting polymorphism.

By using abstraction, you create a higher level of understanding and organization in your code, making it more manageable and adaptable to changes.