Thank you for your reply. Actually this is part of a very large program. Instead, I am providing the comments of the coder right before this line:
// class NewClass inherits from ClassB,
// ClassA handles export/import of DLL
// Enables export and import of functions, data, and objects to and from a DLL.
// It's not necessary if you do not want to export this class for input in other DLLs: