Beautiful, the "September That Never Ended". Pining away for
summer, are we? :-)
--
Allen Brown
http://brown.armoredpenguin.com/~abrown
> So yesterday at dinner, Alan mentioned that he wanted a tool to tell him
> how many days he has left until his vacation. He was thinking that since
> the GNU utilities have options for every possible purpose, GNU "date"
> ought to have the ability to do this.
>
> Unfortunately, "man date" reveals that, in fact, this is beyond the
> power GNU "date".
>
> For some unaccountable reason, I was unable to forget that conversation,
> and despite the fact that Alan said he wrote a script to do the job,
> I wasted a few minutes tonight banging out this:
>
> /* daysuntil.c: Calculate the number of days until a target date
>
> To compile: cc -O -s -o daysuntil daysuntil.c -lm
>
> Example: To calculate the number days until Christmas 2008, type
> "daysuntil 2008 12 25" at the shell prompt.
> */
>
> #include <stdio.h>
> #include <time.h>
> #include <math.h>
>
> long julian(int, int, int);
>
> int main(int argc, char **argv)
> {
> time_t now;
> int y, m, d;
> long nowjd, thenjd;
> struct tm *nowtm;
>
> if(argc!=4) {
> fprintf(stderr, "usage: %s <year> <month> <day>\n",
> argv[0]);
> exit(1);
> }
> y = atoi(argv[1]);
> m = atoi(argv[2]);
> d = atoi(argv[3]);
> time(&now);
> nowtm = localtime(&now);
> nowjd = julian(nowtm->tm_year+1900, nowtm->tm_mon+1,
> nowtm->tm_mday);
> thenjd = julian(y, m, d);
> printf("%ld\n", thenjd-nowjd);
> exit(0);
> }
>
> long julian(int y, int m, int d) /* days since March 1, 1BC */
> {
> m -= 3;
> if(m<0) {
> y -= 1;
> m += 12;
> }
> return 365L*y+y/4-y/100+y/400+(long)floor(30.6001*m+0.5)+d-1;
> }
>
> And then, since I hadn't wasted enough time yet, and since the calculation
> is almost the same, here's one to figure today's date in the September
> That Never Ended:
>
> /* sepdate.c: Today's date in Endless September
>
> To compile: cc -O -s -o sepdate sepdate.c -lm
> */
>
> #include <stdio.h>
> #include <time.h>
> #include <math.h>
>
> long julian(int, int, int);
>
> int main(void)
> {
> time_t now;
> long nowjd, thenjd;
> struct tm *nowtm;
>
> time(&now);
> nowtm = localtime(&now);
> nowjd = julian(nowtm->tm_year+1900, nowtm->tm_mon+1,
> nowtm->tm_mday);
> thenjd = julian(1993, 8, 31);
> printf("Today is September %ld, 1993\n", nowjd-thenjd);
> exit(0);
> }
>
> long julian(int y, int m, int d) /* days since March 1, 1BC */
> {
> m -= 3;
> if(m<0) {
> y -= 1;
> m += 12;
> }
> return 365L*y+y/4-y/100+y/400+(long)floor(30.6001*m+0.5)+d-1;
> }
>
> (In case anybody cares, today is September 5337, 1993.)
>
> So...anybody else program anything useless recently?
>
> - Neil Parker
> _______________________________________________
> EUGLUG mailing list
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> http://www.euglug.org/mailman/listinfo/euglug
>
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