Re: [Boost-users] some problems about shared_ptr

Subject: Re: [Boost-users] some problems about shared_ptr
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2010-09-10 11:38:40

AMDG

Samurai Deeper wrote:
> I am a newbie of C++ and I have some question about the shared_ptr
> I think the best way to explain it is with an example:
>
> /*******beginning of CValue.h*************/
> <snip>
> /****end*************/
>
> /*****Type.h***********/
>
> <snip>
>
> template<typename T, template <typename> class Value>
> struct Type
> {
>   typedef boost::shared_ptr< Value<T> > pValue;  
> };
>
>   

What is the point of Type?  It appears to be gratuitous complexity to me.

> /********end************/
>
>
> what if I want to make it as a composition class?
>   

What do you mean by a composition class?

> by example
>
> /***************example**********/
> #include "Type.h"
> #include "CValue.h"
>
> template<typename T>
> class DIP //digital image processing
> {
>   public:
>     DIP();    
>     virtual ~DIP();
>     shared_ptr < Type<T, filter> >createMediumFilter();
> };
>   

What is filter here?  Also, did you mean the
Type<T, filter>::pValue, aka shared_ptr<filter<T> >?

> <snip>
> /*****************end**************/
>
> I want to create the instance of mediumFilter like this in the main function
>
> int main()
> {        
>   Type<matrix<double>, Composition>::pValue C(new Composition<matrix<double>
>   
>> );
>>     
>   Type<matrix<double>, CValue>::pValue D;
>   D = C->createCValue();  
>
>   cout<<"system pause"<<endl;
>   cin.get();
> }
>
> how could I fix the problems

I've read through this several times, and I'm afraid that
I don't understand what you're trying to do.

In Christ,
Steven Watanabe