Simple C++ program to find circumference and diameter of circle

#include<iostream.h>
#include<conio.h>
int main()
{
clrscr();
int diameter,r;
cout<<"Enter radius of circle:"; //prompt
cin>>r;//input
cout<<"Diameter is:"<<r*2<<endl;
cout<<"Circumference is:"<<2*3.14159*r<<endl;
getch();
return 0;
}