julian-day.c

   1 /* Show the day number (julian calendar) */
   2
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <time.h>
   7
   8 int main(void)
   9 {
  10         char datastr[16];
  11         struct tm *tm;
  12         struct tm date;
  13         time_t timep;
  14
  15         timep = time(NULL);
  16         tm = localtime(&timep);
  17         if (!tm) {
  18                 perror("localtime()");
  19                 exit(1);
  20         }
  21
  22         memset(&date, 0, sizeof(date));
  23         date.tm_yday = tm->tm_yday;
  24         date.tm_year = tm->tm_year;
  25
  26         datastr[0] = '\0';
  27         strftime(datastr, sizeof(datastr), "%j/%Y", &date);
  28         printf("%s\n", datastr);
  29         return 0;
  30 }