C++ Class Definition Publication class and derived classes

#include <iostream>
#include <string>
using namespace std;
class publication
{
   private:/* w ww.ja va2 s  . c o  m*/
   string title;
   float price;
   public:
   virtual void getdata()
   {
      cout << "\nEnter Title:C++  "; cin >> title;
      cout << "Enter price: "; cin >> price;
   }
   virtual void putdata()
   {
      cout << "\n\nTitle:C++  " << title;
      cout << "\nPrice: " << price;
   }
};
class book : public publication
{
   private:
   int pages;
   public:
   void getdata()
   {
      publication::getdata();
      cout << "Enter number of pages: "; cin >> pages;
   }
   void putdata()
   {
      publication::putdata();
      cout << "\nPages: " << pages;
   }
};
class tape : public publication
{
   private:
   float time;
   public:
   void getdata()
   {
      publication::getdata();
      cout << "Enter playing time: "; cin >> time;
   }
   void putdata()
   {
      publication::putdata();
      cout << "\nPlaying time: " << time;
   }
};
int main()
{
   publication* pubarr[100];          //array of ptrs to pubs
   int n = 0;                         //number of pubs in array
   char choice;                       //user's choice
   do {
      cout << "\nEnter data for book or tape (b/t)? ";
      cin >> choice;
      if( choice=='b' )               //make book object
         pubarr[n] = new book;        //   put in array
      else                            //make tape object
         pubarr[n] = new tape;        //   put in array
      pubarr[n++]->getdata();         //get data for object
      cout << "   Enter another (y/n)? ";  //another pub?
      cin >> choice;
   }
   while( choice =='y');              //cycle until not 'y'
   for(int j=0; j<n; j++)             //cycle thru all pubs
      pubarr[j]->putdata();           //print data for pub
   cout << endl;
   return 0;
}