What is the purpose of a virtual destructor in C++?

The purpose of a virtual destructor in C++ is to ensure that when deleting a derived class object through a base class pointer, the destructor of the derived class is correctly called in order to avoid memory leaks and other issues. Without using a virtual destructor, when a base class pointer points to a derived class object and the pointer is deleted, only the base class destructor will be called, not the derived class destructor, which can result in the resources of the derived class not being released properly. By using a virtual destructor, it is ensured that the destructor of the derived class is correctly called when deleting an object, allowing for the release of the corresponding resources.