请求帮助：一个简单的 VC++ API 编程

我刚学VC++不久，下面有一道API编程题，不知道错在哪里，请
指出来，谢谢！
#include <windows.h>
#include <winuser.h>

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

int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInst,
LPSTR lpszCmdLine,
int nCmdShow)
{
HWND hwnd;
MSG Msg;
WNDCLASS wndclass;
char lpszClassName[]="窗口";
char lpszTitle[]="My_Windows";

//
wndclass.style = 0;
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 = lpszClassName;

//
if( !RegisterClass( &wndclass ))
{
MessageBeep(0);
return FALSE;
}

//
hwnd = CreateWindow(lpszClassName,
lpszTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);

//
ShowWindow(hwnd, nCmdShow);
//
UpdateWindow(hwnd);
//
while( GetMessage( &Msg, NULL, 0, 0))
{
TranslateMessage( &Msg );
DispatchMessage( &Msg );
}

return Msg.wParam;
}


//
LRESULT CALLBACK WinProc( HWND hwnd,
UINT message,
WPARAM wParam,
LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
PostQuitMessage(0);
default :
return DefWindowProc(hwnd, message, wParam, lParam);
}
return(0);
}