Object Oriented Programming Questions Long
Abstract classes in Object Oriented Programming (OOP) are classes that cannot be instantiated, meaning we cannot create objects directly from them. Instead, they serve as blueprints or templates for other classes to inherit from.
The main purpose of abstract classes is to provide a common interface or set of methods that subclasses must implement. These methods are declared in the abstract class but do not contain any implementation details. Subclasses that inherit from the abstract class are then responsible for providing the implementation for these abstract methods.
To define an abstract class, we use the "abstract" keyword in the class declaration. This indicates that the class is abstract and cannot be instantiated. However, it can still have regular methods with implementation details, as well as member variables.
One important characteristic of abstract classes is that they can have constructors. These constructors are used to initialize the member variables of the abstract class and can be called by the constructors of the subclasses.
Abstract classes can also have non-abstract methods, which are fully implemented methods that provide common functionality for the subclasses. These methods can be inherited by the subclasses without any modifications.
When a class inherits from an abstract class, it must provide implementations for all the abstract methods declared in the abstract class. Failure to do so will result in a compilation error. This ensures that all subclasses adhere to the contract defined by the abstract class.
Abstract classes are useful when we want to define a common interface or behavior that multiple related classes should have. By using abstract classes, we can enforce consistency and ensure that all subclasses implement the required methods. This promotes code reusability and maintainability, as changes made to the abstract class will automatically propagate to all its subclasses.
In summary, abstract classes in OOP provide a way to define common interfaces and behaviors for subclasses. They cannot be instantiated but serve as blueprints for other classes to inherit from. Abstract classes can have abstract methods that must be implemented by the subclasses, as well as non-abstract methods with implementation details. They promote code reusability and maintainability by enforcing consistency among related classes.