计算下电脑的运算速度

写下面程序来计算下我的电脑的运算速度：

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

void Printlocaltime(void)
{
    struct tm *timeptr;
    time_t secsnow;

    time(&secsnow);
    timeptr=localtime(&secsnow);
    printf("The date is %d-%d-20%02d\n",
          (timeptr->tm_mon)+1,
          (timeptr->tm_mday),
          (timeptr->tm_year)-100);

    printf("Local time is %02d:%02d:%02d\n",
          (timeptr->tm_hour),
          (timeptr->tm_min),
          (timeptr->tm_sec));
}

int main()
{
    Printlocaltime();
    for(int i=0;i<1000000000;i++)
    {}
    printf("\n\n");
    Printlocaltime();
    return 0;
}

运行结果：

The date is 3-26-2012
Local time is 20:05:30

The date is 3-26-2012
Local time is 20:05:34

显然在0.4s内进行了10亿次运算，所以1s的会进行25亿次运算。