函数功能：GetTickCount返回（retrieve）从操作系统启动到现在所经过（elapsed）的毫秒数，它的返回值是DWORD.
知道了这个，这个程序也就不是什么难事了。。。
CODE：
复制代码 代码如下:
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#include <stdio.h>
typedef struct node
{
int h;
int m;
int s;
}
*PTime;
void sleep(long wait);
void gettime();
int main()
{
PTime times;
int flag = 1;
char time[128];
do
{
_strtime(time); // Gets the current system time (do not include the date)
system("cls"); // clear screen
printf("OS time: %s\n",time);
gettime(times); // call gettime()
sleep(1000); // sleep 1 second
printf("已开机时间: %02d小时%02d分%02d秒\n", times->h, times->m, times->s);
}while(flag); // always cycle
return 0;
}
void sleep(long wait)
{
long goal; // define total time
goal = wait + clock();
while(goal > clock());
}
PTime gettime(PTime T)
{
int i = GetTickCount();
T->h = (i / 1000) / 3600;
T->m = (i / 1000) / 60 - T->h * 60;
T->s = (i / 1000) - T->h * 3600 - T->m * 60;
return T;
}