Re: [boost] [ptr_container] Inappropriate behaviours

From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2005-07-29 07:37:49

Hi Allen,

Allen <yaozhen <at> ustc.edu> writes:

> However, I found that the ptr
> container can only "reserve" specfic sized buffered, but cannot be
> constructed with specific size:
> 
>   ptr_vector<nullable<int> > v(10);
> 
> Instead, I have to write this:
> 
>   ptr_vector<nullable<int> > v(10);
>   for (int i = 0; i < 10; i++)
>     v.push_back(0);
> 
> It is really a superise in my opinion, and write a loop (or use an STL
> algorithm) to fill the container manually is awkward and unnecessary. 

I can't test this before I get a computer sgain.

However, I think you should be able to use boost.assign to
fill your ptr_vector. 

>I
> think it is more intuitive and natural that the above constructor
> constructs a ptr_vector of size 10, with 10 null pointers inside. If the
> container is not nullable, it could default-construct 10 objects (or
> clone 10 from a given one) instead.

the problem is that we don't want to make to much differences between
ptr_vector<T> and ptr_vector< nullable<T> >.
If one inserts clones, so should the other--and in my choice, vice versa.

Let's see if boost.assign can't help you.

> Another superise is it seems that the iterator returned by associative
> ptr containers are not std::pair like STL containers do, but the values
> in the associative container. I cannot see the reason for this
> incompatibility with STL, nor can I find any documentation or examples
> on this.

have you read the tutorial?

> Am I missing something? Comments are welcome.

-Thorsten