C$++$ Design a class Publication, which has the following member variables: title,

number$\_$of$\_$pages, year, and price. Derive the following two classes from this class:

$$ Book class adds a member variable author.

$$ Magazine class adds member variables month and yearly$\_$subscription$\_$price.

Include appropriate constructors, and set and get functions for all the classes.

Demonstrate the classes in a complete program.