/* month_name:  return name of n-th month */
   char *month_name(int n)
   {
       static char *name[] = {
           "Illegal month",
           "January", "February", "March",
           "April", "May", "June",
           "July", "August", "September",
           "October", "November", "December"
       };

       return (n < 1 || n > 12) ? name[0] : name[n];
   }