Arizona State University (ASU) CSE240 Introduction to Programming Languages Midterm Practice Exam

An abstract class in Object-Oriented Programming (OOP) serves as a blueprint for other classes and has specific characteristics that set it apart. The correct answer highlights that an abstract class cannot be instantiated directly, meaning you cannot create an object of that class. This is a foundational aspect of abstract classes, as their purpose is to provide common functionality and structure to derived classes while leaving some methods undefined, allowing subclasses to implement these abstract methods according to their specific requirements.

Additionally, an abstract class can contain both abstract methods (which have no implementation and must be overridden by subclasses) and concrete methods (which have a defined implementation). This approach promotes code reusability and enforces a contract for subclasses, ensuring that they provide specific behavior while still benefiting from shared code defined in the abstract class.

The concept of abstract classes is integral to the principles of OOP, particularly in promoting the use of polymorphism and inheritance. By defining an abstract class, developers create a clear interface and structure while allowing flexibility for different implementations in subclasses.