Ребят когда я смогу

#include <Windows.h>
LRESULT CALLBACK WndProc(HWND hWnd,UINT message,WPARAM wParam, LPARAM lParam);
#define WMAIN_CLASSNAME     "WndClassTestMyName???"
#define WMAIN_CAPTION       "WndCaption"
 
int APIENTRY WinMain(HINSTANCE hInst,HINSTANCE hPrev,LPTSTR cmd,int md)
{
    HWND hWnd;
    MSG msg;
    WNDCLASS wc;
    wc.cbClsExtra=0;
    wc.cbWndExtra=0;
    wc.hbrBackground=(HBRUSH)(COLOR_WINDOW+1);
    wc.hCursor=LoadCursor(NULL,IDC_ARROW);
    wc.hIcon=LoadIcon(NULL,IDI_WINLOGO);
    wc.hInstance=hInst;
    wc.lpfnWndProc=WndProc;
    wc.style=CS_HREDRAW | CS_VREDRAW;
    wc.lpszClassName=WMAIN_CLASSNAME;
    wc.lpszMenuName=NULL;
 
    if(!RegisterClass(&wc))
        return 0;
 
    hWnd=CreateWindow(WMAIN_CLASSNAME,WMAIN_CAPTION,/*WS_OVERLAPPEDWINDOW*/WS_OVERLAPPED|WS_CAPTION|WS_SYSMENU|WS_MINIMIZEBOX|WS_MAXIMIZEBOX | WS_VISIBLE,CW_USEDEFAULT,CW_USEDEFAULT,500,300,HWND_DESKTOP,NULL,hInst,0);
 
    if (!hWnd)
        return 0;
 
    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}
 
 
LRESULT CALLBACK WndProc(HWND hWnd,UINT message,WPARAM wParam, LPARAM lParam)
{
    PAINTSTRUCT ps;
    HDC hdc;
    switch (message)
    {
    case WM_SIZE:
        InvalidateRect(hWnd,NULL,true);
        break;
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
 
        EndPaint(hWnd,&ps);
        break;
    case WM_CLOSE:
        if (MessageBox(hWnd,"Close?","Msg Caption",MB_YESNO)==IDYES){
            return DefWindowProc(hWnd,message,wParam,lParam);
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default: 
        return DefWindowProc(hWnd,message,wParam,lParam);
    }
    return 0;
}