Отсутствуют кнопки закрытия, максимизации и минимизации окна

#include <windows.h>
LRESULT CALLBACK HelloWorldWndProc(HWND,UINT,UINT,LONG);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpszCmdParam,int nCmdShow)
{
    HWND hWnd;
    WNDCLASS WndClass;
    MSG Msg;
    char szClassName[]="HelloWorld";
    WndClass.style=CS_HREDRAW|CS_VREDRAW;
    WndClass.lpfnWndProc=HelloWorldWndProc;
    WndClass.cbClsExtra=0;
    WndClass.cbWndExtra=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;
    if (!RegisterClass(&WndClass))
    {
        MessageBox(NULL,"Cannot register class","ERROR",MB_OK);
        return 0;
    }
    hWnd=CreateWindow(szClassName,"Hello World",WS_OVERLAPPED,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL);
    if (!hWnd)
    {
        MessageBox(NULL,"Cannot create window","ERROR",MB_OK);
        return 0;
    }
    ShowWindow(hWnd,nCmdShow);
    UpdateWindow(hWnd);
    while (GetMessage(&Msg,NULL,0,0))
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}
LRESULT CALLBACK HelloWorldWndProc(HWND hWnd,UINT Message,UINT wParam,LONG lParam)
{
    HDC hDC;
    PAINTSTRUCT PaintStruct;
    RECT Rect;
    switch (Message)
    {
        case WM_PAINT:
            hDC=BeginPaint(hWnd,&PaintStruct);
            GetClientRect(hWnd,&Rect);
            DrawText(hDC,"Hello World!",-1,&Rect,DT_SINGLELINE|DT_CENTER|DT_VCENTER);
            EndPaint(hWnd,&PaintStruct);
            return 0;
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
    }
    return DefWindowProc(hWnd,Message,wParam,lParam);
}