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Groups > comp.lang.c++ > #37361
| From | Christopher Pisz <nospam@notanaddress.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: What practice can get speed improvement in C++? |
| Date | 2015-08-06 10:10 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <mpvt9r$tk7$1@dont-email.me> (permalink) |
| References | (4 earlier) <f76c748e-03ed-41ae-8e8c-6bd49b6f9f3c@googlegroups.com> <mpsggk$27e5$1@adenine.netfront.net> <df458bfc-ff61-40e1-b2cf-30782eb9f74b@googlegroups.com> <d2gadrFa455U2@mid.individual.net> <e63cc224-1f12-4fbd-836c-efe42e4f03e2@googlegroups.com> |
On 8/6/2015 12:53 AM, woodbrian77@gmail.com wrote:
> On Thursday, August 6, 2015 at 12:42:31 AM UTC-5, Ian Collins wrote:
>> woodbrian77@gmail.com wrote:
>>>
>>> How about comparing these two programs:
>>>
>>> #include <string.h>
>>>
>>> int main ()
>>> {
>>> for (int i = 0; i < 4000000; ++i){
>>> char s[200];
>>> ::strncpy(s, "We few; we happy few; we band of brothers.", sizeof(s));
>>> }
>>> }
>>>
>>> and
>>>
>>> #include <string>
>>>
>>> int main ()
>>> {
>>> for (int i = 0; i < 4000000; ++i){
>>> ::std::string s = "We few; we happy few; we band of brothers.";
>>> }
>>> }
>>
>> A fairer comparison would be
>>
>> int main ()
>> {
>> std::string s;
>> for (int i = 0; i < 4000000; ++i){
>> s = "We few; we happy few; we band of brothers.";
>> }
>> }
>>
>
>
> Here's the time for that version.
>
> time ./stdstr
>
> real 0m0.120s
> user 0m0.118s
> sys 0m0.001s
>
> In most cases I can't lift a std::string out of the loop like that
> though.
>
A fairer comparison would be
int main ()
{
std::string s;
s.reserve(200);
for (int i = 0; i < 4000000; ++i)
{
s = "We few; we happy few; we band of brothers.";
}
}
--
I have chosen to troll filter/ignore all subthreads containing the
words: "Rick C. Hodgins", "Flibble", and "Islam"
So, I won't be able to see or respond to any such messages
---
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What practice can get speed improvement in C++? fl <rxjwg98@gmail.com> - 2015-07-14 16:53 -0700
Re: What practice can get speed improvement in C++? Barry Schwarz <schwarzb@dqel.com> - 2015-07-14 17:23 -0700
Re: What practice can get speed improvement in C++? bartekltg <bartekltg@gmail.com> - 2015-07-15 15:10 +0200
Re: What practice can get speed improvement in C++? JiiPee <no@notvalid.com> - 2015-07-16 05:00 +0100
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-07-16 01:04 -0700
Re: What practice can get speed improvement in C++? JiiPee <no@notvalid.com> - 2015-07-16 16:48 +0100
Re: What practice can get speed improvement in C++? JiiPee <no@notvalid.com> - 2015-07-16 16:52 +0100
Re: What practice can get speed improvement in C++? bartekltg <bartekltg@gmail.com> - 2015-07-16 13:23 +0200
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-07-16 06:54 -0700
Re: What practice can get speed improvement in C++? bartekltg <bartekltg@gmail.com> - 2015-07-16 17:30 +0200
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-07-16 11:16 -0700
Re: What practice can get speed improvement in C++? bartekltg <bartekltg@gmail.com> - 2015-07-17 17:06 +0200
Re: What practice can get speed improvement in C++? JiiPee <no@notvalid.com> - 2015-08-04 16:14 +0100
Re: What practice can get speed improvement in C++? Victor Bazarov <v.bazarov@comcast.invalid> - 2015-07-14 20:29 -0400
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-07-14 19:50 -0700
Re: What practice can get speed improvement in C++? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2015-07-15 05:07 +0200
Re: What practice can get speed improvement in C++? Lőrinczy Zsigmond <nospam@for.me> - 2015-07-15 06:38 +0200
Re: What practice can get speed improvement in C++? Paavo Helde <myfirstname@osa.pri.ee> - 2015-07-15 00:22 -0500
Re: What practice can get speed improvement in C++? fl <rxjwg98@gmail.com> - 2015-07-16 04:34 -0700
Re: What practice can get speed improvement in C++? Martijn van Buul <pino@dohd.org> - 2015-07-21 09:28 +0000
Re: What practice can get speed improvement in C++? Juha Nieminen <nospam@thanks.invalid> - 2015-08-03 08:16 +0000
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-03 13:48 -0700
Re: What practice can get speed improvement in C++? Juha Nieminen <nospam@thanks.invalid> - 2015-08-04 08:21 +0000
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-08-04 08:07 -0700
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-04 10:15 -0700
Re: What practice can get speed improvement in C++? Bo Persson <bop@gmb.dk> - 2015-08-04 20:09 +0200
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-04 12:38 -0700
Re: What practice can get speed improvement in C++? Bo Persson <bop@gmb.dk> - 2015-08-05 17:03 +0200
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-05 23:32 -0700
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-08-05 03:55 -0700
Re: What practice can get speed improvement in C++? Christopher Pisz <nospam@notanaddress.com> - 2015-08-04 14:09 -0500
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-04 12:18 -0700
Re: What practice can get speed improvement in C++? Christopher Pisz <nospam@notanaddress.com> - 2015-08-04 14:50 -0500
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-08-05 04:11 -0700
Re: What practice can get speed improvement in C++? Juha Nieminen <nospam@thanks.invalid> - 2015-08-05 08:12 +0000
Re: What practice can get speed improvement in C++? Martin Shobe <martin.shobe@yahoo.com> - 2015-08-05 08:53 -0500
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-05 22:24 -0700
Re: What practice can get speed improvement in C++? Ian Collins <ian-news@hotmail.com> - 2015-08-06 17:42 +1200
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-05 22:53 -0700
Re: What practice can get speed improvement in C++? Öö Tiib <ootiib@hot.ee> - 2015-08-06 00:20 -0700
Re: What practice can get speed improvement in C++? Christopher Pisz <nospam@notanaddress.com> - 2015-08-06 10:10 -0500
Re: What practice can get speed improvement in C++? Bo Persson <bop@gmb.dk> - 2015-08-06 17:29 +0200
Re: What practice can get speed improvement in C++? woodbrian77@gmail.com - 2015-08-06 09:38 -0700
Re: What practice can get speed improvement in C++? Juha Nieminen <nospam@thanks.invalid> - 2015-08-10 08:25 +0000
Re: What practice can get speed improvement in C++? pip010 <pip010@gmail.com> - 2015-08-03 04:22 -0700
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