time.h

http://baike.baidu.com/view/1741851.htm#3_6 

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

int main()
{
time_t t;
struct tm *gmt,*area;

t=time(NULL);
area=localtime(&t);
printf("Localtimeis:%s",asctime(area));
gmt=gmtime(&t);
printf("GMTis:%s",asctime(gmt));
return 0;
}