What is the purpose of polymorphism in C++?

Polymorphism in C++ is a feature of object-oriented programming that allows the use of base class pointers or references to operate on derived class objects, enabling the same operation to have different behaviors. The main functions of polymorphism include:

1. By utilizing polymorphism, we can achieve code reuse and extension by using a base class pointer or reference to operate on different derived class objects, thus avoiding the repetition of writing similar code. At the same time, when there is a need to add a new derived class, there is no need to modify existing code, just add the new derived class and keep the base class interface consistent.
2. Simplify code maintenance and modifications: Polymorphism can make code more flexible and extensible. When there is a need to change the behavior of a certain operation, one only needs to modify the corresponding derived class without changing the code that calls that operation.
3. Achieve dynamic binding of functions: Through polymorphism, it is possible to dynamically determine which function to call at runtime. This allows the program to decide which function to call based on the specific object type, thus achieving dynamic binding of functions.
4. Unified interface implementation: By utilizing polymorphism, objects with similar behaviors can be grouped together and operated on using a single base class pointer or reference. This allows for a unified interface, making the code clearer and easier to understand.

In general, polymorphism can enhance the maintainability, scalability, and reusability of code, making it more flexible and reliable.