#include "ruby.h"

VALUE factorial( VALUE self, VALUE index )
{
  VALUE fact = Qnil;
  long i = NUM2LONG( index );
  long f = 1;
  while(i>0){
    f = f * i--;
  }
  fact = LONG2NUM( f );
  return( fact );
};

Init_ext_fact1()
{
  rb_define_global_function("factorial", factorial, 1 );
};