学步园

from：《Solaris系统编程》Rich Teer : 141.

例1：确定闰年

#include <stdio.h>
#include <stdlib.h>
#include "ssp.h"

int main (int argc, char **argv)
{
        int y;
        int ly;

        if (argc != 2)
                err_quit ("Usage: leap_year year");

        y = atoi (argv [1]);

        ly = (y % 4 == 0) ? ((y % 100 == 0) ? ((y % 400 == 0) ? 1 : 0) : 1) : 0;

        printf ("%d %s a leap year/n", y, (ly == 0) ? "is not" : "is");

        return (0);
}

例2：Solaris提供了tm结构，方便了封装日期。

#include <stdio.h>
#include <time.h>

int main (void)
{
        struct tm *tp;
        time_t login;
        time_t logout;
        time_t session_length;

        login = 100000;
        logout = 200000;
        session_length = (time_t) difftime (logout, login);

        tp = gmtime (&session_length);

        printf ("Session length is %d days, %d hours, %d minutes, "
                "and %d seconds/n", tp -> tm_yday, tp -> tm_hour, tp -> tm_min,
                tp -> tm_sec);

        return (0);
}
运行结果：

-bash-3.00$ ./gmtime
Session length is 1 days, 3 hours, 46 minutes, and 40 seconds

#include <stdio.h>
#include <time.h>

int main (void)
{
        struct tm tp;
        char *wday [] = {
                "Sunday", "Monday", "Tuesday", "Wednesday",
                "Thursday", "Friday", "Saturday", "Unknown"
        };

        tp.tm_sec = 1;
        tp.tm_min = 0;
        tp.tm_hour = 0;
        tp.tm_mday = 18;
        tp.tm_mon = 9 - 1;
        tp.tm_year = 1967 - 1900;
        tp.tm_isdst = -1;

        if (mktime (&tp) == -1)
                tp.tm_wday = 7;

        printf ("September 18th, 1967 was a %s./n", wday [tp.tm_wday]);

        return (0);
}
运行结果为：

-bash-3.00$ ./mktime
September 18th, 1967 was a Monday.