Mencari Volume Ball alias Bola

#include <iostream>
#include <string>

using namespace std;
int main()
{
string raptor_prompt_variable_zzyz;
int r;
int Phi;
int Volume_Bola;

Phi =3,14;
raptor_prompt_variable_zzyz ="Masukkan r :";
cout << raptor_prompt_variable_zzyz << endl;
cin >> r;
Volume_Bola =4/3*Phi*r*r*r;
cout << Volume_Bola << endl;

system("PAUSE");
return 0;
}