Hi folks,

I just read the C++-FAQ and I liked it very much.

However there are a few things I would like to get some feedback on.

==============================================================================
Q69: How are `private derivation' and `containment' similar? dissimilar?
A: Private derivation can be thought of as a syntactic variant of containment
(has-a).  Ex: it is NOT true that a privately derived is-a-kind-of-a Base:

With private derivation:
 class Car : private Engine {/*...*/}; //a Car is NOT a-kind-of Engine
Similarly:
 class Car { Engine e; /*...*/ }; //normal containment
==============================================================================

I would NOT say that private derivation ALWAYS equals containment.

e.g.

 class MyRaceCar : private Citroen2PK {/*...*/}

Certainly I haven't put a Citroen2PK IN MyRaceCar.

MyRaceCar is-a-kind-of-a Citroen2PK but rather a special one that I don't
like 'derivators' to play with.  In fact nobody has business about how I
turned the Citroen2PK into MyRaceCar.

==============================================================================
Q80: What is a `virtual constructor'?

Here is an example of how you could use `clone()' and `fresh()' methods:
 class Set {  //normally this would be a template
 public:
   virtual void insert(int); //Set of `int'
   virtual int  remove();
   //...
   virtual Set& clone() const = 0; //pure virtual; Set is an ABC
   virtual Set& fresh() const = 0;
   virtual ~Set() { } //see on `virtual destructors' for more
 };

 class SetHT : public Set {
   //a hash table in here
 public:
   //...
   Set& clone() const { return *new SetHT(*this); }
   Set& fresh() const { return *new SetHT(); }
 };
==============================================================================

I wonder who is ever going to delete s.clone() and s.fresh() ?

Is there anybody who is willing to give his brief point of view
about virtual constructors (and clone()) ? I know this is FAQ but
I am just reacting upon FAQ ...

==============================================================================
Q99: What is `virtual data', and how-can / why-would I use it in C++?
==============================================================================

I liked that one !

In fact here each new is in concert with a delete.

VStack(int cap=10) : v(*new Vec(cap)), sp(0) { } //FREESTORE

~VStack() {delete &v;} //NECESSARY

 -- marc.

New person question:  where is the C++ FAQ kept?  Please response via email.
Thank you.

Chris Gennaula
Cray Research, Inc.
cjg@cray.com