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/* TIMES.C illustrates various time and date functions including:
 *      time            ftime           ctime       asctime
 *      localtime       gmtime          mktime      tzset
 *      _strtime        _strdate        strftime
 *
 * Also the global variable:
 *      tzname
 */
 
#include <time.h>
#include <stdio.h>
#include <sys\types.h>
#include <sys\timeb.h>
#include <string.h>
 
void main()
{
    char tmpbuf[128], ampm[] = "AM";
    time_t ltime;
    struct timeb tstruct;
    struct tm *today, *gmt, xmas = { 0, 0, 12, 25, 11, 88 };
 
    /* Set time zone from TZ environment variable. If TZ is not set,
     * PST8PDT is used (Pacific standard time, daylight savings).
     */
    tzset();
 
    /* Display DOS-style date and time. */
    _strtime( tmpbuf );
    printf( "DOS time:\t\t\t\t%s\n", tmpbuf );
    _strdate( tmpbuf );
    printf( "DOS date:\t\t\t\t%s\n", tmpbuf );
 
    /* Get UNIX-style time and display as number and string. */
    time( &ltime );
    printf( "Time in seconds since GMT 1/1/70:\t%ld\n", ltime );
    printf( "UNIX time and date:\t\t\t%s", ctime( &ltime ) );
 
    /* Display GMT. */
    gmt = gmtime( &ltime );
    printf( "Greenwich Mean Time:\t\t\t%s", asctime( gmt ) );
 
    /* Convert to time structure and adjust for PM if necessary. */
    today = localtime( &ltime );
    if( today->tm_hour > 12 )
    {
        strcpy( ampm, "PM" );
        today->tm_hour -= 12;
    }
    /* Note how pointer addition is used to skip the first 11 characters
     * and printf is used to trim off terminating characters.
     */
    printf( "12-hour time:\t\t\t\t%.8s %s\n",
            asctime( today ) + 11, ampm );
 
    /* Print additional time information. */
    ftime( &tstruct );
    printf( "Plus miliseconds:\t\t\t%u\n", tstruct.millitm );
    printf( "Zone difference in seconds from GMT:\t%u\n", tstruct.timezone );
    printf( "Time zone name:\t\t\t\t%s\n", tzname[0] );
    printf( "Daylight savings:\t\t\t%s\n", tstruct.dstflag ? "YES" : "NO" );
 
    /* Make time for noon on Christmas, 1988. */
    if( mktime( &xmas ) != (time_t)-1 )
        printf( "Christmas\t\t\t\t%s\n", asctime( &xmas ) );
 
    /* Use time structure to build a customized time string. */
    today = localtime( &ltime );
 
    /* Use strftime to build a customized time string. */
    strftime( tmpbuf, 128, "Today is %A, day %d of %B in the year %Y.\n", today );
    printf( tmpbuf );
}