时间函数

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

int main(void)
{
 time_t tt;
 struct tm * ttm;
 
 //获取本机时间
 tt = time(NULL);
 
 printf("UTC time = %ld\n", tt);
 
 printf("current time is: %s", ctime(&tt));
 
 //转换成本地时间
 ttm = localtime(&tt);
 printf("local time is: %s", asctime(ttm));
 
 printf("local time:\n"
   "\t%d-%d-%d : %d-%d-%d\n"
   "\tweekday %d\n"
   "\tyearday %d\n",
   ttm->tm_year+1900,
   ttm->tm_mon+1,
   ttm->tm_mday,
   ttm->tm_hour,
   ttm->tm_min,
   ttm->tm_sec,
   ttm->tm_wday,
   ttm->tm_yday);
 
 //格林威治时间
 ttm = gmtime(&tt);
 printf("gm time is: %s", asctime(ttm));

 printf("gm time:\n"
   "\t%d-%d-%d : %d-%d-%d\n"
   "\tweekday %d\n"
   "\tyearday %d\n",
   ttm->tm_year+1900,
   ttm->tm_mon+1,
   ttm->tm_mday,
   ttm->tm_hour,
   ttm->tm_min,
   ttm->tm_sec,
   ttm->tm_wday,
   ttm->tm_yday);

 return 0;
}