Помощь с MFC

#include "stdafx.h"
#include "Практика.h"

#define MAX_LOADSTRING 100

HINSTANCE hInst;                               
TCHAR szTitle[MAX_LOADSTRING];                 
TCHAR szWindowClass[MAX_LOADSTRING];           
int Storona=10, Speed=5, Time=0;

ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK Parametr(HWND, UINT, WPARAM, LPARAM);


class Guk
{
public:
    Guk(int,int,HDC);
    void Delete(HDC);
private:
    int x,y;

};

Guk::Guk(int a, int b, HDC hdc)
{
    HBRUSH hbrush;
    x=a;
    y=b;
    hbrush=CreateSolidBrush(BLACK_BRUSH);
    SelectObject(hdc,hbrush);
    Ellipse(hdc,x-5,y-5,x+5,y+5);
    DeleteObject(hbrush);
};

void Guk::Delete(HDC hdc)
{
    COLORREF color=RGB(255,255,255);
    HPEN hpen;
    hpen=CreatePen(PS_SOLID,0,color);
    SelectObject(hdc,hpen);
    Ellipse(hdc,x-5,y-5,x+5,y+5);
    DeleteObject(hpen);
};

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    MSG msg;
    HACCEL hAccelTable;

    LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadString(hInstance, IDC_MY, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_MY));

    while (GetMessage(&msg, NULL, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_MY));
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCE(IDC_MY);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance;

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;

    switch (message)
    {
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        switch (wmId)
        {
        case IDM_about :
            DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
            break;
        case IDM_EXIT:
            DestroyWindow(hWnd);
            break;
        case ID_FILE_PARAMETR:
            DialogBox(hInst, MAKEINTRESOURCE(IDD_PARAM), hWnd, Parametr);
            break;
        case ID_FILE_CLEAR:
            InvalidateRect(hWnd,NULL,1);

            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_LBUTTONDOWN:
        {
            int k;
            HDC hdc;
            hdc=GetDC(hWnd);
            SetTimer(hWnd,1,10,NULL);
            k=30*Storona;
            MoveToEx(hdc,50,50,NULL);
            Rectangle(hdc, 50,50,50+k, 50+k);
            Guk A(50,50,hdc);
            Guk B(50+k,50,hdc);
            Guk C(50,50+k,hdc);
            Guk D(50+k,50+k,hdc);
            ReleaseDC(hWnd, hdc);};
        break;
    case WM_TIMER:
        Time++;
        break;
       
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}


INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

INT_PTR CALLBACK Parametr(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        {
            wchar_t s1[20]; _itow_s(Speed, s1, 10);
            wchar_t s2[20]; _itow_s(Storona, s2, 10);

            SetDlgItemText(hDlg, IDC_VALUE1, s1);
            SetDlgItemText(hDlg, IDC_VALUE2, s2);
        }
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            char s1[20];
            GetDlgItemText(hDlg, IDC_VALUE1, (LPWSTR)s1, sizeof(s1)-1);
            char s2[20];
            GetDlgItemText(hDlg, IDC_VALUE2, (LPWSTR)s2, sizeof(s2)-1);
            int v1 = _wtoi((LPWSTR)s1);
            int v2 = _wtoi((LPWSTR)s2);

            Speed=v1;
            Storona=v2;
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}