/*****
                              valid_date()

      This function determines whether a date is valid.

   Argument list:    int month      the month
                     int day        the day
                     int year       the year

   Return value:     int            1 if valid, 0 if not

*****/

int valid_date(int day, int month, int year)
{
   static int days[] = {0, 31, 28, 31, 30, 31, 30,
                           31, 31, 30, 31, 30, 31};

   if (month > 12 || month < 1 || day > 31 || day < 1)
      return 0;

   if (day > days[month]) {
      if (month == 2 && day == 29) {   /* Special check for leap year */
         if (leapyear(year)) {
            return 1;
         }
      }
      return 0;
   }
   return 1;
}