/* juldate.c - convert dates */

Julian_to_Gregorian(inday, year, month, day)  /* julian day to month and day */
register short int inday;
int  *year, *month, *day;
{
   register short int leap_year, m;
   static short month_days[] = {       /* in leap year */
        0,  31,  60,  91, 121, 152,
      182, 213, 244, 274, 305, 335, 366};
#define APRIL 92
#define JUNE 183
#define SEPTEMBER 275

   leap_year = ((*year % 4) == 0);   /* approximately */
   if (!leap_year && (inday > 59)) inday++;
   if (inday < JUNE)
     m = (inday < APRIL) ? 0 : 3;
   else
     m = (inday < SEPTEMBER) ? 6 : 9;

   for ( ; inday > month_days[m]; m++);   /* find month */
   *day = inday - month_days[m-1] + 1;
   *month = m;
}