Re: Question on Style regarding initialization for inter-working classes

From:
=?ISO-8859-1?Q?Marcel_M=FCller?= <news.5.maazl@spamgourmet.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 08 May 2008 09:12:35 +0200
Message-ID:
<4822a823$0$7538$9b4e6d93@newsspool1.arcor-online.net>
Hi,

nomail@invalid.com schrieb:

The question is, should the Environment class hold an instance of
the Output class, or just a pointer?


use the pointer. You will never be able to deal with different outputs
otherwise.

If it had an instance, then I would need to create new constructors
in the Environment class in order to pass the string. This seems
kinda clunky, as now I have modified the environment in order to
appease some other class.


Exactly.

It does have the advantage of
initialization of all classes at once.

The alternative would be for the Environment class to use a pointer to
the Output class, but the Output class would have to initialized
outside the environment class, and then the pointer set. From a
program perspective, this just takes a couple of extra steps,
but I need to make sure that the pointer is always set.


Not neccessarily, see below.

I may have already answered my question if I want inheritance
for the Output class (the pointer method would work better), but


Exactly.

I was wondering in terms of style if there is a better
style/method/whatever.


Use a factory for the output class. The environment may invoke this
factory to get an apropriate output. The factory should know how to
initialize the output before it is invoked. So it takes no parameters
from the Environment.
This makes the initialization of an environment instance one line. Of
course you have to configure the factory first, but only once.

Marcel

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