Цикл y=1+x+x^2+x^3+...+x^n; - C++

#include <cmath>
#include <conio.h>
#include <iostream>
using namespace std;
int main()
{
double x;
cout << "x = ";
cin >> x;
double n;
cout << "n = " ;
cin >> n;
double S=1;
for (int i=1; i<=n; i++)
S+=pow(x,i);
cout << "S = " << S;
getch();
}