Run Time Polymorphism

#include<iostream.h>
#include<stdlib.h>
#include<time.h>
#include<conio.h>
class shape
{
public:
virtual char typeof()=0;
};
class circle:public shape
{
private:
int xc,yc,radius;
public:
circle(int x,int y,int r)
{
xc=x;
yc=y;
radius=r;
}
char typeof()
{
return 'C';
}
};
class rectangle:public shape
{
private:
int x1,y1,x2,y2;
public:
rectangle(int xx1,int yy1,int xx2,int yy2)
{
x1=xx1;
y1=yy1;
x2=xx2;
y2=yy2;
}
char typeof()
{
return 'R';
}
};
void main()
{
clrscr();
shape *s[5];
int i,num;
randomize();
for(i=0;i<=4;i++)
{
num=random(2);
if(num==0)
s[i]=new circle(10,20,15);
else
s[i]=new rectangle(11,12,15,70);
}
for(i=0;i<=4;i++)
cout<<endl<<s[i]->typeof();
getch();
}