#include <sys/time.h> #include <stdio.h> #include <math.h>/*     accurate to usec*/void getusertime(){    static struct timeval tpstart,tpend;     static float timeuse;     static int count=0;    count++;    if ((count%2)==1)            gettimeofday(&tpstart,NULL);    else    {        gettimeofday(&tpend,NULL);                  timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+             tpend.tv_usec-tpstart.tv_usec;         timeuse/=1000000;           printf("count:%d  Used Time:%f\n",count,timeuse);     }}void testfunction() { unsigned int i,j; double y; for(i=0;i<1000;i++) for(j=0;j<1000;j++) y=sin((double)i); } void test(){    getusertime();          testfunction();         getusertime();}int main(int argc,char** argv) {        for(int i=0;i<10;i++)        test();        }