[Dev-C++] operator+ and inheritance

[<or...@vp...>]

Hi!

I have a question regarding operator overloading and inheritance. I have=20
a base class with some data. And I also have a derived class from base,=20
which extends base with even more data. I have defined an operator+ for=20
the base.
My question is: how can I define an operator+ for the drived class, so=20
it will copy both the base and dervied data. Must I call the base=20
operator+ from the derived operator+ explicitly?
I have thought of something like this:

class Base
{
public:
	Base operator+( const Base& b )
	{
		Base sum;
	=09
		sum.m_BaseData1 =3D b.m_BaseData1 + m_BaseData1;
		sum.m_BaseData2 =3D b.m_BaseData2 + m_BaseData2;
	=09
		return sum;
	}

	int m_BaseData1;
	int m_BaseData2;

}; // Base

class Derived
{
public:
	Derived operator+( const Derived& d )
	{
		Derived sum;

		// assign "this + d" to sum:
		sum =3D Base::operator+( d );
		sum.m_DerivedData1 =3D d.m_DerivedData1 + m_DerivedData1;
		sum.m_DerivedData2 =3D d.m_DerivedData2 + m_DerivedData2;
	=09
		return sum;
	}

	int m_DerivedData1;
	int m_DerivedData2;

}; // Derived


Is that correct?
And if so, my next "problem" is, that an assignment operator needs to be=20
used in the Derived operator+. Can that be "solved" (removed) somehow?

Thanks in advance.

--
Greetings,
   Bal=E1zs