void func1 (int &x) {
   x = 9 * x;
}

void func2 (int v[]) {
   v[0] = 9 * v[0];
}

int main (void) {
   int x, v[2];
   x    = 111; 
   func1 (x); printf ("x: %d\n", x);
   v[0] = 111; 
   func2 (v); printf ("v[0]: %d\n", v[0]);
   return 0;
}