[PIU] Wymiary i położenie okna

#include <windows.h>
#include <stdio.h>

TCHAR ClassName[] = TEXT("Klasa");
int okna = 0;
HWND NoweOkno;
RECT R;
unsigned int W, S;

static void Rysuj(const HWND okno123)
{
    HDC Kontekst;
    PAINTSTRUCT Informacje;
    static const size_t txt_size = 64;

    Kontekst = BeginPaint(okno123, &Informacje);
    GetClientRect(okno123, &R);

    wchar_t txt[64];
    wchar_t txt2[64];

    swprintf(txt, txt_size, TEXT("Rozmiar: %i, %i"), R.right, R.bottom);
    swprintf(txt2, txt_size, TEXT("Pozycja: %i x %.2i "), W, S);

    SetTextColor(Kontekst, RGB(0, 255, 0));
    SetBkColor(Kontekst, RGB(20, 0, 20));

    TextOut(Kontekst, 5, 5, txt, wcslen(txt));
    TextOut(Kontekst, 5, 50, txt2, wcslen(txt2));

    EndPaint(okno123, &Informacje);
}

LRESULT CALLBACK WndProc(HWND okno, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_PAINT:
        Rysuj(okno);
        break;
    case WM_CREATE:
        ++okna;
        UpdateWindow(okno);
        break;
    case WM_SIZE:
        InvalidateRect(okno, &R, 1);
        break;
    case WM_MOVE:
        InvalidateRect(okno, &R, 1);
        W = LOWORD(lParam);
        S = HIWORD(lParam);
        break;
    case WM_LBUTTONDOWN:
        NoweOkno = CreateWindowEx(0, ClassName, TEXT("Nowe Okno"), WS_OVERLAPPEDWINDOW, 100, 100, 500, 300, 0, 0, GetModuleHandle(0), 0);
        ShowWindow(NoweOkno, SW_SHOW);
        UpdateWindow(NoweOkno);
        break;
    case WM_DESTROY:
        if (okna == 0)
        {
            MessageBox(0, TEXT("KONIEC!"), TEXT(""), MB_OK);
            PostQuitMessage(0);
        }
        break;
    case WM_CLOSE:
        if (MessageBox(0, L"Zamknac to okno?", L"", MB_YESNO | MB_ICONQUESTION) == IDYES)
        {
            okna--;
            DestroyWindow(okno);
        }
        break;
    default:
        return DefWindowProc(okno, msg, wParam, lParam);
        break;
    }
    return 0;
}

static int RejestrujKlase()
{
    WNDCLASSEX wc;
    wc.cbClsExtra = 0;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.hCursor = 0;
    wc.hIcon = 0;
    wc.hIconSm = 0;
    wc.hInstance = GetModuleHandle(0);
    wc.lpfnWndProc = WndProc;
    wc.lpszClassName = ClassName;
    wc.lpszMenuName = 0;
    wc.style = 0;
    if (!RegisterClassEx(&wc))return 0;
}

static void WyrejestrujKlase()
{
    UnregisterClass(ClassName, GetModuleHandle(0));
}


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLIne, int nShowCmd)
{
    HWND okno1;
    HWND okno2;
    HWND okno3;
    MSG msg;

    if (!RejestrujKlase())
    {
        MessageBox(0, TEXT("Nie udało się zarejestrować klasy okna!"), TEXT("UWAGA"), MB_ICONSTOP | MB_OK);
        return 1;
    }

    okno1 = CreateWindowEx(0, ClassName, L"Okno1", WS_OVERLAPPEDWINDOW, 100, 100, 500, 300, 0, 0, hInstance, 0);
    ShowWindow(okno1, nShowCmd);
    UpdateWindow(okno1);

    okno2 = CreateWindowEx(0, ClassName, L"Okno2", WS_OVERLAPPEDWINDOW, 100, 100, 500, 300, 0, 0, hInstance, 0);
    ShowWindow(okno2, nShowCmd);
    UpdateWindow(okno2);

    okno3 = CreateWindowEx(0, ClassName, L"Okno3", WS_OVERLAPPEDWINDOW, 100, 100, 500, 300, 0, 0, hInstance, 0);
    ShowWindow(okno3, nShowCmd);
    UpdateWindow(okno3);


    while (GetMessage(&msg, 0, 0, 0)>0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    UnregisterClass(ClassName, hInstance);


    WyrejestrujKlase();
    return 0;
}