Run time polymorphism

/*program to implement runtime polymorphism*/
#include<conio.h>
#include<iostream>
#include<string.h>
using namespace std;
class media
{
	protected:char title[30];
				float price;
	public :media(char *s,float a)
			{
				strcpy(title,s);
				price=a;
			}
			virtual void display()
			{
			}
};
class book :public media
{
	int pages;
	public :book(char *s,float a,int p):media(s,a)
			{
				pages=p;
			}
			void display()
			{
				cout<<"\nTitle: "<<title;
				cout<<"\nPages: "<<pages;
				cout<<"\nPrice: "<<price;
			}
};
class tape :public media
{
	float time;
	public:tape(char *s,float a,float t):media(s,a)
			{
				time=t;
			}
			void display()
			{
				cout<<"\nTitle: "<<title;
				cout<<"\nRuntime: "<<time<<"hr";
				cout<<"\nPrice: "<<price;
			}
};
int main()
{
	char *title=new char[30];
	float price,time;
	int pages;

	cout<<"\nBook details:"<<endl;
	cout<<"Enter Title:";
	cin>>title;
	cout<<"Enter Price:";
	cin>>price;
	cout<<"Enter Pages:";
	cin>>pages;
	book book1(title,price,pages);

	cout<<"\nTape details:"<<endl;
	cout<<"Enter Title:";
	cin>>title;
	cout<<"Enter Price:";
	cin>>price;
	cout<<"Enter Runtime in hours:";
	cin>>time;
	tape tape1(title,price,time);

	media *list;
	list=&book1;
	cout<<"Book details:"<<endl;
	list->display();
	list=&tape1;
	cout<<"Tape details:"<<endl;
	list->display();
	getch();
	return 0;
}