Re: [Boost-users] adding elements to a std::container in a

Subject: Re: [Boost-users] adding elements to a std::container in a
From: Martin Elzen (martinelzen_at_[hidden])
Date: 2011-08-14 09:48:46

> Subject: [Boost-users] adding elements to a std::container in a single
> 	expression
> Message-ID: <j2787j$bj9$1_at_[hidden]>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
> 
> until now I've usually written my own template to do this:
> 
> 
> template<typename T>
> struct push_back_container:T
> {    push_back_container &_push_back(const typename T::value_type &_r)
>     {    push_back(_r);
>         return *this;
>     }
> };
> 
> one can use this like this:
> 
> push_back_container<std::vector<something> 
>  >()._push_back(something1)._push_back(_something2)
> 
> Is there some more elegant way to do this?

Been there, and had the same issues.  I've always wondered why std::vector gives you so many ways to assign values to it, but so few to append items, as personally I want to append items much more often than totally change a vector's contents.  For what you want to do there is also a standard assign-with-back-inserter whatchamacallit :

include vector
include algorithm // assign
include iterator    // back_inserter

std::copy( 
   source.begin(), source.end(), 
   std::back_inserter( targetSequenceWithpush_back_memberFn ) 
);