即时显示时间

#include <iostream>
#include <iomanip>
#include <ctime>
#include <windows.h>
using namespace std;
int main()
{
time_t ti = time(NULL);
struct tm* timer = localtime(&ti);
while(1)
{
cout << setfill('0') << setw(2) << timer->tm_hour << ":" <<setw(2) << timer->tm_min << ":" << setw(2) << timer->tm_sec << "\r";
Sleep(1000);//睡眠一秒钟
if(++timer->tm_sec >= 60)//秒
{
     timer->tm_sec = 0;
     if(++timer->tm_min >= 60)//分
{
     timer->tm_min = 0;
     if(++timer->tm_hour >= 24)//时
        timer->tm_hour = 0;
}
}
}
return 0;
}