Re: block allocation

From:

Victor Bazarov <v.bazarov@comcast.invalid>

Newsgroups:

comp.lang.c++

Date:

Thu, 08 Sep 2011 11:27:58 -0400

Message-ID:

<j4amtu$1vm$1@dont-email.me>

On 9/8/2011 11:15 AM, Philipp Kraus wrote:

On 2011-09-08 17:09:01 +0200, Noah Roberts said:

On Sep 8, 6:57 am, Philipp Kraus <philipp.kr...@flashpixx.de> wrote:

Hello,

I would like to allocate a lot of objects in a block. I have read that
I can use calloc (and free), but I think it is a C call and I would do
this in C++-style. I need around 100 till 100.000 objects in memory and
I would do this like:

std::vector<myclass> objects;
for(size_t i=0; i < maxsize; ++i)
objects.push_back( myclass(...) );

If "..." is always the same then you can initialize the entire vector
on construction:

std::vector<myclass> objects(maxsize, myclass(...));

I can't call my constructor, I need call a method named "clone()". I
create a call like:

std::vector<myclass> vec(p_size);
for(std::size_t i=0; i < p_size; ++i)
vec.psuh_back( myclass.clone() );

can I do it like:

std::vector<myclass> vec(p_size, myclass.clone()) with the same result?

No. 'myclass.clone()' in that case would only be called once, and the
vector is going to be filled by copying that one clone. There is
probably a way to utilize a lambda in combination with std::fill or
std::copy.

V
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