計算下電腦的運算速度

寫下面程式來計算下我的電腦的運算速度：

#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;
}

運行結果：

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

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

顯然在0.4s內進行了10億次運算，所以1s的會進行25億次運算。