Re: pure operator=
* Mike -- Email Ignored:
Pure operator= thus:
class A // abstract
{
virtual A& operator=(const A&); // has a purpose
};
class B : public A // never instantiated alone
{
virtual B& operator=(const B&) = 0; // nothing needed, so pure
};
class C : public B; // instantiated
Extranous semicolon.
{
virtual C& operator=(const C&); // has a purpose
};
Won't compile as long as I leave the assignment operator for
class B pure. Why not?
You haven't defined any of the three different assignment operators you
have declared.
Also, they're all private.
But apart from the extranous semicolon noted above, I can't see why the
code shown above shouldn't compile if you supply a main(); it's just
declarations.
Chapter & verse?
That's not what you need.
What you need is to know that virtual assignment operators are generally
a very bad idea -- for they imply run-time type checking.
Cheers, & hth.,
- Alf
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