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From: Neal Becker (ndbecker2_at_[hidden])
Date: 2005-06-01 11:48:18

christopher diggins wrote:

> ----- Original Message -----
> From: "Neal Becker" <ndbecker2_at_[hidden]>
> To: <boost_at_[hidden]>
> Sent: Wednesday, June 01, 2005 8:33 AM
> Subject: [boost] Re: Boost Array Initialization Technique
>> Loïc Joly wrote:
>>> AlisdairM a écrit :
>>>> Aggregate initialization is an important part of the array concept,
>>>> allowing it to act largely as a plug-in replacement for language
>>>> arrays, with the bonus it can be passed by value as well as by
>>>> reference. The main drawback here is that we cannot deduce the size of
>>>> a boost::array, as you can with a language array.
>>> From my point of view, the main drawback is that in the following code:
>>> vector<double> v1(6);
>>> array<double, 6> v2;
>>> v1's content is initialized, v2's content is not. In fact, array is
>>> about the only class I know of that as a default constructor that does
>>> not initialize member data to a legal and documented value. This I
>>> strongly dislike.
>>> By the way, I also dislike the fact that double d; does not initialize
>>> d, but at least people know that fundamental type do not behave well
>>> when initialization is concerned.
>> I strongly disagree. Forcing initialization makes code that is not
>> useful
>> for high performance numerical processing. When we declare a container
>> of 1000000 elements, we don't want to waste time initializing each,
>> unless we want to.
> I think the best solution in this case is to use an alternative
> "collection" for numerical processing. Using a class intended as general
> purpose array for numerical processing I think would not be a good idea.

I still disagree. Depending on default initialization is like depending on
init of static variables to 0. If you really need a special init value, be
explicit and say so. I see no logic to the default construct of complex to
have 0 value. The only logic to default construct values I can see is
where there truly is a sensible default for a parameter.

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