VC中让软件发出Beep声，用Beep函数，另需添加头文件， #include <windows.h>，例如，Beep(1000,500);
Syntax
C++
BOOL WINAPI Beep(_In_ DWORD dwFreq,_In_ DWORD dwDuration );
Parameters
-
dwFreq [in]
-
The frequency of the sound, in hertz. This parameter must be in the range 37 through 32,767 (0x25 through 0x7FFF).
dwDuration [in]
-
The duration of the sound, in milliseconds.
延迟函数如下，
int sTime, eTime;
sTime = ::GetTickCount();
eTime = ::GetTickCount();
while (eTime - sTime < 500)
{
MSG msg;
GetMessage(&msg, NULL, 0, 0);
TranslateMessage(&msg);
DispatchMessage(&msg);
eTime = ::GetTickCount();
}
使用Sleep函数，或者使用循环来导致延迟，会出现窗口死的情况，用以上函数则没有，或者使用Timer和线程也可以。
转载：
在一个对话框中访问另一个对话框的变量
HWND mHwnd = ::FindWindow(NULL,"dlgok");//通过windowname得到该窗体的句柄
DlgOk* mDlgok= (DlgOk*)CWnd::FromHandle(mHwnd ); //有该句柄得到对话框类的指针
int ntemp= mDlgok->m_temp; //访问其中的变量