Dave Harris wrote:
In-Reply-To: <005501c566b3$1fc76eb0$2b792518@heronnest> cdiggins@videotron.ca (christopher diggins) wrote (abridged):
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 doubt we need a whole class. A special argument might do, to let us choose:
boost::array<int,1000> b( boost::uninitialised ); boost::array<int,1000> b( boost::initialised );
That's a reasonable proposition. But for the initialized case, you want to be specifying a value to initialize to - zero is *not* a reasonable default for all circumstance.
The question for me is what the default should be. And in my view, the default should be safe rather than fast.
From what I gather, and the commentary you make below, I seriously beg to differ. Back to the year dot with C & C++ we've never had such a thing as pre-initialization of arrays and it'd be a bad time to start such a movement now. Furthermore, for persons like myself writing plenty of numerical code, and algorithmic development - the default better be the fastest and with a minimalist take on assumptions - as always ... trust the developer to know what they are doing.
---- For what it's worth, I think auto variables, std::complex and even std::vector should be the same: initialised by default but with uninitialised available as an option. And since this is now a language change, perhaps "boost::initialised" should be spelt "?" for brevity.
int x; // x == 0. int y = ?; // y is uninitialised. int *px = new int; // *px == 0. int *py = new int( ? ) // *py is uninitialised. vector<int> vx( 100 ); // vx.front() is 0. vector<int> vy( 100, ? );
Please let's not go down this path; and as for vectors, we can opt to initialize on construction - I can't see the benifit of such a proposal, but to safeguard against the forgetful. my $0.02 Cheers, -- Manfred Doudar MetOcean Engineers www.metoceanengineers.com