extending an stl container and iterator to also find groups of elements

[alan.f22]

HI

First off, thanks for taking the time to read this.

I have an class inheritance hierachy say:
base class "E" and a bunch of derived classes (from "E") "A",
"P", and "S"

I have an STL vector (might change to a list) std::vector<Ewhich is
populated by
A's, P's, and S's

Certain sequences of A's, P's and S's can be grouped to form other
classes (composite):
class M consists of one P and one S
class C consists of one A and any number of M's

What I am looking for is a way to extend/modify the STL container/
iterator to:
Allow me to iterate though the single vector using different types of
iterators:
i.e. vector<E*>::iterator, vector<M*>::iterator, vector<C*>::iterator,
vector<A*>::iterator

Basicly I'm looking to be able to iterate a single vector/list in a
number of different ways so I don't have to maintain multiple vectors/
lists for each of the composite types and specific operations I have
to perform.
Thanks for any advice and input
- A

[Ian Collins]

al******@gmail.com wrote:

HI

First off, thanks for taking the time to read this.

I have an class inheritance hierachy say:
base class "E" and a bunch of derived classes (from "E") "A",
"P", and "S"

I have an STL vector (might change to a list) std::vector<Ewhich is
populated by
A's, P's, and S's

I doubt that, all a vector of E can hold is E objects. Did you intend
to write std::vector<E*>?

Certain sequences of A's, P's and S's can be grouped to form other
classes (composite):
class M consists of one P and one S
class C consists of one A and any number of M's

Explain "consists of". Are you using multiple inheritance with virtual
bases or does an M have a P and an S as members?

What I am looking for is a way to extend/modify the STL container/
iterator to:
Allow me to iterate though the single vector using different types of
iterators:
i.e. vector<E*>::iterator, vector<M*>::iterator, vector<C*>::iterator,
vector<A*>::iterator

If you want to do this, there is probably something broken in your design.

Basicly I'm looking to be able to iterate a single vector/list in a
number of different ways so I don't have to maintain multiple vectors/
lists for each of the composite types and specific operations I have
to perform.

What problem are you trying to solve this way that you can't solve
through polymorphism and virtual methods?

--
Ian Collins.