C++动态时间显示

#include <iostream>
#include<stdlib.h>
#include<windows.h>
#include<string>
using namespace std;
int main()
{
    string week = " ";
    while ()
    {
        SYSTEMTIME systemTime;
        GetLocalTime(&systemTime);
        cout << "当前时间是：" << systemTime.wYear << "年" << systemTime.wMonth << "月" << systemTime.wDay << "日";
        cout << systemTime.wHour << "时" << systemTime.wMinute << "分" << systemTime.wSecond << "秒";
        switch (systemTime.wDayOfWeek)
        {
        case :
            week = "日";
            break;
        case :
            week = "一";
            break;
        case :
            week = "二";
            break;
        case :
            week = "三";
            break;
        case :
            week = "四";
            break;
        case :
            week = "五";
            break;
        case :
            week = "六";
            break;
        }
        cout << "   星期";
        cout << week << endl;
        Sleep();
        system("cls");
    }
    return ;

}