What is Need of virtual class while building class hierarchy?

Virtual classes are essential in building class hierarchies because they enable polymorphism, allowing derived classes to override base class methods. This ensures that the correct method implementation is called based on the object's actual type at runtime, enhancing code flexibility and maintainability. Additionally, virtual classes facilitate dynamic binding, allowing developers to create more modular and extensible code structures. Overall, they help in designing robust systems that can adapt to changes and new requirements efficiently.