Program for Newton's Law of Gravitation

In this program user inputs the mass of two bodies and the distance between them and calculate and output the Force of attraction between two masses according to Newton's law of gravitation.

#include<iostream.h>
#include<conio.h>
#include<math.h>
void main()
{
clrscr();
float f,m1,m2,r;
cout<<"Enter the value of two masses in Kg : ";
cin>>m1>>m2;
cout<<"Enter the distance between two masses in meters : ";
cin>>r;
f=(6.67*pow(10.0,-11.0)*m1*m2)/(r*r);
cout<<"The force of attraction between two masses = "<<f<<" Newton ";
getch();
}