C++ Polymorphism Methods

In C++, there are several ways to achieve polymorphism.

1. Virtual function: By declaring a function as virtual in the base class, subclasses can override it to achieve different functionalities. When calling a virtual function, the corresponding function will be called based on the actual type of the object.
2. A pure virtual function is declared in the base class, and any subclass must implement this function, otherwise the subclass will also become an abstract class. When calling the pure virtual function through a pointer or reference to the base class, the corresponding function based on the actual type of the object will be invoked.
3. Virtual function table (VFT): In C++, dynamic binding is achieved through the virtual function table, which is created for each class that contains virtual functions. This table stores the addresses of the virtual functions. When a virtual function is called, the compiler will search the VFT based on the object’s type and then invoke the corresponding function.
4. Virtual function pointer: Every class object that has virtual functions will have a virtual function pointer pointing to the virtual function table, enabling dynamic binding.
5. Abstract class contains pure virtual functions and is unable to be instantiated, but can be utilized as a base class for implementing polymorphism through subclasses.