// Oldham, Jeffrey D.
// 2000Mar22
// CS1321

// Factorial Program

#include <iostream>
#include <stdlib.h>		// has EXIT_SUCCESS

long factorial(const long n) {
  if (n <= 1)
    return n;
  else
    return n * factorial(n-1);
}

int main(int argc, char * argv[])
{
  if (argc != 2) {
    cerr << argv[0] << ": factorial-argument" << endl;
    throw "incorrect number of command-line arguments";
  }

  cout << "Hello, world.\n";
  long n = strtol(argv[1], static_cast<char **>(0), 0);
  cout << factorial(n) << endl;
  cout << "Hello, world.\n";
  return EXIT_SUCCESS;
}