Alexander this is what i have, could you help me how to implement it in this code.

//funciones para dibujo
void CMouseDlg::DrawSquare(int X, int Y){
// Get the Device Context
CClientDC dc(this);
CBrush BackColor(dc.GetBkColor());

if ((m_iPrevX != X) || (m_iPrevY != Y)){
// Draw a square based on coord
dc.Rectangle(m_iPrevX, m_iPrevY, X, Y);
m_iPrevX = -1;
m_iPrevY = -1;
}
}


void CMouseDlg::DrawCircle(int X, int Y){
// Get the Device Context
CClientDC dc(this);

if ((m_iPrevX != X) || (m_iPrevY != Y)){
// Draw a ellipse based on coord
dc.Ellipse(m_iPrevX, m_iPrevY, X, Y);
m_iPrevX = -1;
m_iPrevY = -1;
}
}

I am starting in vc++ and this is a little project of University.