// Total mass of spheres of radii 1, 3, and 7
// with densities 7.87, 8.96, 11.36 respectively
// using function arguments and returned value
#include <iostream>
#include <math.h>
using namespace std;
const double pi = 3.1416;

double SphereMass(double r, double rho) // value of type double 
                                        // will be returned
{
  double volume = 4./3. * pi * r * r * r;
  double mass = rho * volume;
  return mass; // mass (not volume) as returned value of function;
}

int main()  
{
  double m1 = SphereMass(1., 7.87); // returned value assigned to m1
  double m2 = SphereMass(3., 8.96);
  double m3 = SphereMass(7., 11.36);
  cout << m1 + m2 + m3 << endl;
}