Re: Template question

From:

"Grizlyk" <grizlyk1@yandex.ru>

Newsgroups:

comp.lang.c++

Date:

Fri, 9 Mar 2007 14:13:52 +0300

Message-ID:

<esrfij$jbl$1@aioe.org>

Jeroen wrote:

I have a question which is illustrated by the following piece of code:

template <class T>
class A {
T my_value;
};

In a list, I'd like to store pointers to objects of class A. But I don't
know at forehand if these will be A<int> or A<double> or whatever (all
these flavours of A must be stored in the same list). And, lateron if I
retrieve the objects from the list I may have to know what flavour the
object was in order to call the proper routines for processing them.

My question: what does the list look like in C++? I'm lost, so if anyone
has some advice....

Design pattern "adapter" can be used to adapt templated class into virtual
base interface.

class Base
{
public:
    virtual void method()=0;
    virtual ~Base(){}
};

template<class T>
class A_Base: public Base
{
A<T> data;

public:
    void method(){ data.method(); }
};

Multiple ingeritance also can be used

template<class T>
class A_Base: public Base, public A<T>
{
public:
    void method(){ A<T>::method(); }
};

--
Maksim A. Polyanin
http://grizlyk1.narod.ru/cpp_new

"In thi world of fairy tales rolls are liked olso"
                               /Gnume/