typedef long time_t;

这个可以计算#include<stdio.h> 
#include<time.h> 
#define D (24*60*60)
#define H (60*60)
#define M (60)
int main() 
{ 
time_t t; 
time(&t); 
long time=t%D;
int h=time/H;
time=time%H;
int m=time/M;
time=time%M;
int s=time;
printf("time is %02d:%02d:%02d\n",h,m,s); 
return 0; 
}