用C获得当前系统时间.doc

#include #include void main () time_t rawtime; struct tm * timeinfo; time ( &rawtime ); timeinfo = localtime ( &rawtime ); printf ( 007The current date/time is: %s, asctime (timeinfo) ); exit(0); = #include - 必须的时间函数头文件 time_t - 时间类型（time.h 定义） struct tm - 时间结构，time.h 定义如下： int tm_sec; int tm_min; int tm_hour; int tm_mday; int tm_mon; int tm_year; int tm_wday; int tm_yday; int tm_isdst; time ( &rawtime ); - 获取时间，以秒计，从1970年1月一日起算，存于rawtime localtime ( &rawtime ); - 转为当地时间，tm 时间结构 asctime （）- 转为标准ASCII时间格式： 星期 月 日 时：分：秒 年 = 你要的格式可这样输出： printf ( %4d-%02d-%02d %02d:%02d:%02dn,1900+timeinfo-tm_year, 1+timeinfo-tm_mon, timeinfo-tm_mday,timeinfo-tm_hour,timeinfo-tm_min,timeinfo-tm_sec); 就是直接打印tm，tm_year 从1900年计算，所以要加1900， 月tm_mon，从0计算，所以要加1Example /* 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 #include #include #include #include void main() char tmpbuf128, ampm = AM; time_t ltime; struct _timeb tstruct; struct tm *today, *gmt, xmas = 0, 0, 12, 25, 11, 93 ; /* Set time zone from TZ environment variable. If TZ is not set, * the operating system is queried to obtain the default value * for the variable. */ _tzset(); /* Display operating system-style date and time. */ _strtime( tmpbuf ); printf( OS time:tttt%sn, tmpbuf ); _strdate( tmpbuf ); printf( OS date:tttt%sn, tmpbuf ); /* Get UNIX-style time and display as number and string. */ time( ime ); printf( Time in seconds since UTC 1/1/70:t%ldn, ltime ); printf( UNIX time and date:ttt%s, ctime( ime ) ); /* Display UTC. */ gmt = gmtime( ime ); printf( Coordinated universal time:tt%s, asctime( gmt ) ); /* Convert to time structure and adjust for PM if necessary. */ today = localtime( tm_hour 12 ) strcpy( ampm, PM ); today-tm_hour -= 12; if( today-tm_hour = 0 ) /* Adjust if midnight hour. */ 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:tttt%.8s %sn, asctime( today ) + 11, ampm ); /* Print additional time information. */ _ftime( &tstruct ); printf( Plus milliseconds:ttt%un, litm ); printf( Zone difference in seconds from UTC:t%un, tstruct.timezone ); printf( Time zone name:tttt%sn, _tzname0 ); printf( Daylight savings:ttt%sn, tstruct.dstflag ? YES : NO ); /* Make time for noon on Christmas, 1993. */ if( mktime( &xmas ) != (time_t)-1 ) printf( Christmastttt%sn, asctime( &xmas ) ); /* Use time structure to build a customized time string. */ today = localtime( ime ); /* 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 ); Output OS time: 21:51:03 OS date: 05/03/94 Time in seconds since UTC 1/1/70: 768027063 UNIX time and date: Tue May 03 21:51:03 1994 Coordinated universal time: Wed May 04 04:51:03 1994 12-hour time: 09:51:03 PM Plus milliseconds: 279 Zone