What are abstract classes and how do they differ across programming languages?

What are abstract classes and how do they differ across programming languages?

Abstract classes are classes that cannot be instantiated on their own and are meant to be subclassed. They can define methods that must be implemented by subclasses, allowing for a common interface while enabling different implementations.

Can you give me examples of abstract classes in Java and Python?

In Java, you can define an abstract class using the abstract keyword. For example:

abstract class Animal {
    abstract void sound();
}

In Python, you can use the abc module:

from abc import ABC, abstractmethod

class Animal(ABC):
    @abstractmethod
    def sound(self):
        pass

How do abstract classes help in software design?

Abstract classes promote code reusability and establish a clear contract for subclasses, ensuring that they implement specific methods. This leads to better organization and maintainability of code.

Are there any languages that don't support abstract classes?

Yes, some languages like JavaScript do not have built-in support for abstract classes, but you can achieve similar behavior using prototypes or by convention.