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Re: STL vector

Newsgroups comp.lang.c++
Subject Re: STL vector
References <op.v4z6q8m5vc68pg@hp2011.workgroup> <KGFwq.32258$zC6.5650@en-nntp-15.dc1.easynews.com>
Date 2011-11-16 08:58 +0100
From "Peter Liedermann" <peter09876@hispeed.ch>
Message-ID <op.v404e2clvc68pg@hp2011.workgroup> (permalink)
Organization hispeed.ch

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On Wed, 16 Nov 2011 03:59:56 +0100, Joe Gottman  
<josephgottman@comcast.net> wrote:

> On 11/15/2011 2:50 PM, Peter Liedermann wrote:
>> Hi there,
>>
>> Let "Jumbo" be the name of a class whose instances consume substantial
>> storage.
>>
>> A vector of typically 1000 such Jumbo-instances is needed. It must be
>> sorted by a simple int criterium, but not often.
>>
>> Is there a substantial performance difference between vector <Jumbo> and
>> vector <Jumbo *>, provided that everything else is adapted accordingly?
>> Is there a difference at all?
>>
>> Thanx a lot,
>> Peter
>>
>
>    1) If you know in advance the size of the vector, you can reserve the  
> right amount of capacity before you start filling it and thus avoid the  
> costs of reallocation.

yes, I do

>
>    2) If you can define an efficient swap() function for your class,  
> then sorting a vector<Jumbo> would not involve any copying whatever.
>
I can certainly swap Jumbo * (pointers) easily, swapping Jumbo objects  
themselves is certainly (much?) more difficult.
So I am determined to use Jumbo * as of now.
Thanx for the clarification
Peter

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Thread

STL vector "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-15 20:50 +0100
  Re: STL vector Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-11-15 21:30 +0100
    Re: STL vector Leigh Johnston <leigh@i42.co.uk> - 2011-11-15 21:13 +0000
      Re: STL vector Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-11-15 22:46 +0100
        Re: STL vector Leigh Johnston <leigh@i42.co.uk> - 2011-11-15 22:02 +0000
          Re: STL vector / Heap fragmentation "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-16 09:02 +0100
            Re: STL vector / Heap fragmentation Goran <goran.pusic@gmail.com> - 2011-11-16 00:39 -0800
              Re: STL vector / Heap fragmentation "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-16 10:58 +0100
                Re: STL vector / Heap fragmentation Goran <goran.pusic@gmail.com> - 2011-11-16 04:12 -0800
    Re: STL vector "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-16 08:55 +0100
      Re: STL vector yatremblay@bel1lin202.(none) (Yannick Tremblay) - 2011-11-16 16:54 +0000
      Re: STL vector Joe Gottman <josephgottman@comcast.net> - 2011-11-16 18:22 -0500
  Re: STL vector Joe Gottman <josephgottman@comcast.net> - 2011-11-15 21:59 -0500
    Re: STL vector "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-16 08:58 +0100
  Re: STL vector Werner <werasm@gmail.com> - 2011-11-16 05:53 -0800
  Re: STL vector Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 14:02 +0000
    Re: STL vector Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 14:05 +0000
    Re: STL vector "Peter Liedermann" <peter09876@hispeed.ch> - 2011-11-17 16:45 +0100
      Re: STL vector Leigh Johnston <leigh@i42.co.uk> - 2011-11-17 16:19 +0000
      Re: STL vector Joshua Maurice <joshuamaurice@gmail.com> - 2011-11-17 15:19 -0800

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