1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <sys/time.h>
 5 int    time_substract(struct timeval *result, struct timeval *begin,struct timeval *end)
 6 {
 7     if(begin->tv_sec > end->tv_sec)    return -1;
 8     if((begin->tv_sec == end->tv_sec) && (begin->tv_usec > end->tv_usec))    return
 
 -2;
 9     result->tv_sec    = (end->tv_sec - begin->tv_sec);
10     result->tv_usec    = (end->tv_usec - begin->tv_usec);
11     
12     if(result->tv_usec < 0)
13     {
14         result->tv_sec--;
15         result->tv_usec += 1000000;
16     }
17     return 0;
18 }
19 int main(int
 
 argc, char **argv)
20 {
21     struct timeval start,stop,diff;
22     memset(&start,0,sizeof(struct timeval));
23     memset(&stop,0,sizeof(struct timeval));
24     memset(&diff,0,sizeof(struct timeval));
25     gettimeofday(&start,0);
26     //做你要做的事...
27     printf("hello world\n");
28     gettimeofday(&stop,0
 
);
29     time_substract(&diff,&start,&stop);
30     printf("Total time : %d s,%d us\n",(int)diff.tv_sec,(int)diff.tv_usec);
31 }