#include <iostream>
#include <cstdarg>

using namespace std;

int product(int n, ...)
{ va_list L;
  va_start(L, n);
  int r = 1;
  for (int i = 1; i <= n; i += 1)
    r *= va_arg(L, int);
  va_end(L);
  return r; }

int main()
{ cout << "2 3 4 5: " << product(4, 2, 3, 4, 5) << "\n";
  cout << "8 9: " << product(2, 8, 9) << "\n";
  cout << "2 3 4 5 6 7: " << product(6, 2, 3, 4, 5, 6, 7) << "\n";
  cout << ": " << product(0) << "\n"; }

/* it will print

2 3 4 5: 120
8 9: 72
2 3 4 5 6 7: 5040
: 1

*/