Re: object arrays and constuctors

From:
"James Kanze" <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Wed, 21 Mar 2007 13:06:57 CST
Message-ID:
<1174473270.179382.20300@y80g2000hsf.googlegroups.com>
On Mar 20, 6:37 pm, "tripleF" <s...@night.co.uk> wrote:

I want to pass parameters to the consructors when i create an array of
objects like this for a single object

Object *pSprite;

pSprite=new Object(1,1);

dynamicly created object array

Object *pSprite;

pSprite=new Object[5];

How do i combine the two?


If all objects in the array should have the same initializer:

    std::vector< Object > v( 5, Object( 1, 1 ) ) ;

otherwise:

    std::vector< Object > v( iter1, iter2 ) ;

You'll need some fancy iterators. I'd design Object so that it
only needed a single argument, an std::pair, or a boost::tuple,
if that's what it takes. The iterator returns this argument.
Alternatively, the iterator returns an Object, which is copied.

I'd seriously look into the Boost iterator adapters if I had to
do something like this. I believe they have a counting iterator
adapter, for example.

Note, however, that the usual idiom for this is something along
the lines of:

    std::vector< Object > v ;
    for ( int i = 0 ; i < 5 ; ++ i ) {
        v.push_back( Object( ... ) ) ;
    }

Depending on the source of your initializers, this might be just
as easy and as clear.

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