Re: How to pass STL containers (say a vector) ?

From:

"Daniel T." <postmaster@verizon.net>

Newsgroups:

comp.lang.c++

Date:

Fri, 19 May 2006 19:32:23 GMT

Message-ID:

<postmaster-C980AC.15324419052006@news.west.earthlink.net>

In article <1148063503.729070.325510@j33g2000cwa.googlegroups.com>,
"peter koch" <peter.koch.larsen@gmail.com> wrote:

Daniel T. skrev:

In article <Wahbg.228$D_5.37@fe12.lga>,
Sanjay Kumar <nospam-hypertree@yahoo.com> wrote:

Folks,

I am getting back into C++ after a long time and I have
this simple question: How do pyou ass a STL container
like say a vector or a map (to and from a function) ?

The same way the standard algorithms do. 'std::copy' for example accepts
a container as an input param, and another container as an output param.

Well.... that one is a bad example. std::copy does not return a
collection. Actually, i can't remember a single std::algorithm that
does so (but I am tired and might well be wrong).
In my opinion you need very strong arguments (and those arguments
include measured improvements) in order to not return by value.

I beg to differ, std::copy does return a container in its own way...

vector<int> foo;
copy( istream_iterator<int>( cin ), istream_iterator<int>(),
   back_inserter( foo ) );

The data in foo was returned...

In other words when you want to pass in a container:

   tempalte < typename InIt >
void func( InIt first, InIt last );

when you want to return a container:

   template < typename OutIt >
void func( OutIt first );