uva 11332 - Summing Digits

Problem link
#include <iostream>
#include <cstdio>
using namespace std;

int g(int x) {
 if (x/10==0) return(x);
 int sum=0;
 while (x>0)
 {
  sum+=(x%10);
  x/=10;
 }
 return(g(sum));
}

int main() {
 int n;
 cin >> n;
 while (n)
 {
  cout << g(n) << endl;
  cin >> n;
 }
 return 0;
}