#include <windows.h>      

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
        

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
        
                   PSTR szCmdLine, int iCmdShow)
        
{
        
    static TCHAR szAppName[] = TEXT ("HelloWin") ;
        
    HWND   hwnd ;
        
    MSG    msg ;
        
    WNDCLASS wndclass ;
        
    
   wndclass.style = CS_HREDRAW | CS_VREDRAW |CS_NOCLOSE;
        
   wndclass.lpfnWndProc  = WndProc ;
        
    wndclass.cbClsExtra   = 0 ;
        
    wndclass.cbWndExtra   = 0 ;
        
    wndclass.hInstance    = hInstance ;
        
    wndclass.hIcon        = LoadIcon (NULL, IDI_APPLICATION) ;
        
  wndclass.hCursor      = LoadCursor (NULL, IDC_ARROW) ;
        
   wndclass.hbrBackground= (HBRUSH) GetStockObject (WHITE_BRUSH) ;
        
  wndclass.lpszMenuName   = NULL ;
        
    wndclass.lpszClassName= szAppName ;
        

    if (!RegisterClass (&wndclass))
        
    {
        
            MessageBox (  NULL, TEXT ("This program requires Windows NT!"),
        
                                  szAppName, MB_ICONERROR) ;
        
            return 0 ;
        
    }
        
    hwnd = CreateWindow( szAppName,      // window class name
        
                   TEXT ("The Hello Program"),   // window caption
        
                   WS_OVERLAPPEDWINDOW,  // window style
        
                   CW_USEDEFAULT,// initial x position
        
                   CW_USEDEFAULT,// initial y position
        
                   CW_USEDEFAULT,// initial x size
        
                   CW_USEDEFAULT,// initial y size
        
                   NULL,                 // parent window handle
        
               NULL,            // window menu handle
        
               hInstance,   // program instance handle
        
               NULL) ;      // creation parameters
        
   
        
    ShowWindow (hwnd, iCmdShow) ;
        
    UpdateWindow (hwnd) ;
        
   
        
    while (GetMessage (&msg, NULL, 0, 0))
        
    {
        
            TranslateMessage (&msg) ;
        
          DispatchMessage (&msg) ;
        
    }
        
    return msg.wParam ;
        
}
        

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
        
{
        
    HDC                   hdc ;
        
    PAINTSTRUCT ps ;
        
    RECT          rect ;
        
   
        
    switch (message)
        
    {
        
    case WM_CREATE:
        
    PlaySound (TEXT ("hellowin.wav"), NULL, SND_FILENAME | SND_ASYNC) ;
        
            return 0 ;
        

    case   WM_PAINT:
        
            hdc = BeginPaint (hwnd, &ps) ;
        
        
        
            GetClientRect (hwnd, &rect) ;
        
        
        
            DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,
        
                   DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;
        
                 EndPaint (hwnd, &ps) ;
        
        
     return 0 ;   
        
        
    case   WM_DESTROY:
        
            PostQuitMessage (0) ;
        
            return 0 ;
        
    }
        
  return DefWindowProc (hwnd, message, wParam, lParam) ;
        
}

这是我看来的一个程序，但是我在用VC＋＋编译的时候却出现了下面的错误：
--------------------Configuration: sadf - Win32 Debug--------------------
Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/sadf.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

sadf.exe - 2 error(s), 0 warning(s)
希望那位同仁能帮忙解决一下，顺便解释一下，感激不尽～～～谢谢