求大神， C语言的问题

#include

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR szCmdLine,
int iCmdShow
){
static TCHAR szClassName[] = TEXT("Hello World");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;

wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbClsExtra = 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 = szClassName;

RegisterClass(&wndclass);

hwnd = CreateWindow(
    szClassName,
    TEXT("Welcom"),
    WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT,
    CW_USEDEFAULT,
    500,
    300,
    NULL,
    NULL,
    hInstance,
    NULL
);

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_PAINT:
    hdc = BeginPaint(hwnd, &ps);
    GetClientRect(hwnd, &rect);
    DrawText(
        hdc,
        TEXT("你好， window10欢迎你！"),
        -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);

}

怎么不出现窗口？ 哪里写错了

wndlass结构体参数不对。

 wndclass.cbClsExtra = 0;
 wndclass.cbClsExtra = 0;

应修改为：

wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;