// Class defining a circle object
class CCircle : public CElement
{
public:
    virtual void Draw(CDC* pDC) const;  // Function to display circle

    // Constructor for a circle object
    CCircle(const CPoint& Start, const CPoint& End, const COLORREF& Color );

protected:
    CCircle() {}  // Default constructor - should not be used
};


////////// Circle //////////////////////

// CCircle class constructor 
CCircle::CCircle(const CPoint& Start, const CPoint& End, const COLORREF& Color )
{
    // First calculate the radius
    // We use floating point because that is required by
    // library function in (math.h) for calculating a square root.
    long Radius =
       static_cast<long>(sqrt(static_cast<double>((End.x - Start.x)*
                      (End.x - Start.x) + (End.y - Start.y)*(End.y - Start.y))));

    // Now calculate the rectangel enclosing
    // the circle assuming the MM_TEXT mapping mode
    m_EnclosingRect = CRect( Start.x - Radius, Start.y - Radius,
                             Start.x + Radius, Start.y + Radius );

    m_Color = Color;      // Set Circle color
    m_Pen = 1;            // Set pen width
  
}

// Draw a Circle object
void CCircle::Draw( CDC* pDC ) const
{
    // Create a new pen for this object and
    // initialize it to the object color and line width
    CPen aPen;
    if (!aPen.CreatePen(PS_SOLID, m_Pen, m_Color ))
    {
       AfxMessageBox("Pen creation failed drawing a rectangle", MB_OK );
       AfxAbort();
    }

    // Select the pen
    CPen* pOldPen = pDC->SelectObject( &aPen );

    // Select the brush
    CBrush* pOldBrush = static_cast<CBrush*>(pDC->SelectStockObject(NULL_BRUSH));

    // Now draw the rectangle
    pDC->Ellipse( m_EnclosingRect );

    pDC->SelectObject( pOldBrush );   // Restore old brush
    pDC->SelectObject( pOldPen );     // Restore old pen
}