Enumerted type
===============

/* Compute the next day. */

enum day {sun, mon, tue, wed, thu, fri, sat};

typedef   enum day   day;

day find_next_day(day d)
{
   day   next_day;

   switch (d) {
   case sun:
      next_day = mon;
      break;
   case mon:
      next_day = tue;
      break;
   .....
   case sat:
      next_day = sun;
      break;
   }
   return next_day;
}


/* Compute the next day with a cast. */

enum day {sun, mon, tue, wed, thu, fri, sat};

typedef   enum day   day;

day find_next_day(day d)
{
    return ((day)(((int) d + 1) % 7));
}