Imagine a publishing company that markets both book and audiocassette versions of its

works. Create a class publication that stores the title $($a string$)$ and price $($type float$)$

of a publication. From this class derive two classes: book, which adds a page count $($type

int$),$ and tape, which adds a playing time in minutes $($type float$).$ Each of these three

classes should have a getdata$()$ function to get its data from the user at the keyboard,

and a putdata$()$ function to display its data.

a$)$

Write a main$()$ program to test the book and tape classes by creating instances of them, asking the user to fill in data with getdata$(),$ and then displaying the data with putdata$().$

b$)$

Write a main$()$ program that creates an array of pointers to publication. Assign the pointers in this array in a loop. In the loop, ask the user for data about a particular book or tape, and use new to create an object of type book or tape to hold the data. Put the pointer to the object in the array. When the user has finished entering the data for all books and tapes, display the resulting data for all the books and tapes entered, using a for loop and a single statement such as

pubarr$[$j$]->$putdata$()$;

to display the data from each object in the array.