如何从CreateWindowEx()窗口获取宽度和高度？C++

WNDCLASSEX wc;

wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = "MyWindowClass";
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

if (!RegisterClassEx(&wc))
{
    MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
    return 0;
}

HWND hWnd = CreateWindowEx(WS_EX_CLIENTEDGE, "MyWindowClass", "My Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

RECT rect;
GetClientRect(hWnd, &rect);
int width = rect.right - rect.left;
int height = rect.bottom - rect.top;