Can an abstract class have implementation in object oriented programming ?

Absolutely! Abstract classes in object-oriented programming can definitely have implementations. In fact, it's quite common for them to do so. While having some abstract methods (methods declared without an implementation) is a defining characteristic of an abstract class, it's not the only one. Here's how implementation works in abstract classes:

1. Concrete and Abstract Methods:

• Concrete methods: These are methods within the abstract class that have a complete implementation, defining exactly what they do. Subclasses can inherit these methods and use them directly without needing to reimplement them.
• Abstract methods: These are methods declared without an implementation, forcing subclasses to provide their own specific behavior for them. This encourages specialization and ensures consistency across subclasses that share the same interface.

2. Benefits of Implementation:

• Code reuse: Concrete methods within the abstract class can be reused by subclasses, saving development time and effort.
• Partial implementation: By providing common functionality through concrete methods, you can give subclasses a solid foundation to build upon, simplifying their design.
• Encapsulation: You can hide internal implementation details of the abstract class while still exposing useful functionality via concrete methods.

3. Example:

Imagine an abstract class Shape with:

• Concrete method: getArea(): This calculates the area based on a property like radius or side length, providing a common function for all shapes.
• Abstract method: draw(): This requires each subclass (e.g., Circle, Square) to define its own specific drawing logic.

By combining implementation and abstraction, we achieve a balance between common functionality and specific behavior tailoring.

💡Remember:

• Subclasses must implement all abstract methods declared in the parent class unless they themselves are declared abstract.
• An abstract class cannot be directly instantiated (you can't create objects of its type).
• Implementation in abstract classes should focus on common functionality, leaving room for specialization through abstract methods.