Re: copying Vector elements into Dynamic Array

From:
 James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 24 Jul 2007 13:29:23 -0000
Message-ID:
<1185283763.370330.164380@57g2000hsv.googlegroups.com>
On Jul 24, 1:39 pm, arnuld <geek.arn...@gmail.com> wrote:

On Tue, 24 Jul 2007 12:51:12 +0200, Bo Persson wrote:
Even cleaner code would be
std::copy(ivec.begin(), ivec.end(), pdarr);

Let the standard library decide how to do a copy properly.


WOW man, it works .... what can be the code for printing
the elements of that array to std::cout ?


There is an ostream_iterator, which would allow:

    std::copy( v.begin(), v.end(),
               std::ostream_iterator< int >( std::cout, "\n" ) ) ;

In practice, it's not very useful, because you usually need to
handle additional formatting chores: only 10 to a line,
separator, rather than terminator, etc. Which means you end up
with something like:

    int inLineCount = 0 ;
    for ( std::vector< int >::const_iterator it = v.begin() ;
            it != v.end() ;
            ++ it ) {
        if ( inLineCount == 0 ) {
            std::cout << lineHeader ;
        } else {
            std::cout << inlineSeparator ;
        }
        std::cout << *it ;
        ++ inLineCount ;
        if ( inLineCount == maxInLine ) {
            std::cout << completeLineTermiator ;
            inLineCount = 0 ;
        }
    }
    if ( inLineCount != 0 ) {
        std::cout << partialLineTerminator ;
    }

If you want to use something like a comma separator, attached to
the preceding element, then you'll also need logic to handle
that (something that checks whether (it + 1) == v.end() in the
loop).

--
James Kanze (GABI Software) email:james.kanze@gmail.com
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