Re: Simple inheritance-template question

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From	Ian Collins <ian-news@hotmail.com>
Newsgroups	comp.lang.c++
Subject	Re: Simple inheritance-template question
Date	Thu, 14 Apr 2011 21:51:40 +1200
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On 04/14/11 09:26 PM, crea wrote:
> I cannot find solution to this:
>
> Here is the structure:
>
> template<class T>  class Data
> {
> public:
>   T p;
> };
>
> class AA
> {
> public:
> // here I would like to have a data member: m_data
> };
>
> class BB : public AA
> {
> public:
> };
>
> If an object is create from AA then I want it to have member data object
> created like this:
> Data<int>  m_data;
>
> But if an object is created from BB then I want:
>
> Data<string>  m_data;
>
> How to create a member data variable according to what class the object is
> created from? Is this even possible?

No, not really.  To do so would break the "is a" rule (a BB isn't an 
AA).  Maybe make Data a union rather than a template?

What problem are you trying to solve?

-- 
Ian Collins

Thread

Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 10:26 +0100
  Re: Simple inheritance-template question Ian Collins <ian-news@hotmail.com> - 2011-04-14 21:51 +1200
    Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 11:12 +0100
      Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 11:29 +0100
      Re: Simple inheritance-template question Goran <goran.pusic@gmail.com> - 2011-04-14 03:56 -0700
        Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 12:19 +0100
          Re: Simple inheritance-template question Goran <goran.pusic@gmail.com> - 2011-04-14 04:58 -0700
            Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 13:25 +0100
            Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 13:38 +0100
              Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 13:48 +0100
                Re: Simple inheritance-template question Goran <goran.pusic@gmail.com> - 2011-04-14 06:06 -0700
    One template solution I know, but... "crea" <no@invalid.com> - 2011-04-14 11:41 +0100
      Re: One template solution I know, but... Victor Bazarov <v.bazarov@comcast.invalid> - 2011-04-14 09:32 -0400
        Re: One template solution I know, but... "crea" <no@invalid.com> - 2011-04-14 15:19 +0100
  Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-14 10:59 +0100
    Re: Simple inheritance-template question Noah Roberts <dont@email.me> - 2011-04-14 09:29 -0700
      Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-15 07:50 +0100
      Re: Simple inheritance-template question "crea" <no@invalid.com> - 2011-04-17 17:22 +0100

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