Friday, March 18, 2016

Digest for comp.lang.c++@googlegroups.com - 19 updates in 6 topics

bitrex <bitrex@de.lete.earthlink.net>: Mar 18 07:18PM -0400

Suppose for the sake of argument I have following private constexpr in a
class:
 
static constexpr uint16_t square_it(uint16_t x)
{
return std::pow(x, 2);
}
 
Then I want to construct a static constant array of these values for the
integers up to 255 in the same section of the same class using the above
constexpr:
 
static const uint16_t array_of_squares[256] =
{
//something
};
 
What is the "proper" way to do this?
Lynn McGuire <lmc@winsim.com>: Mar 18 05:55PM -0500

Well, I just got educated on virtual method calls in constructors and destructors. None will be executed as you think so that
functionality will not work. It would be nice if the compiler would warn a person.
http://stackoverflow.com/questions/12092933/calling-virtual-function-from-destructor
and
http://stackoverflow.com/questions/9114982/calling-virtual-method-from-destructor-workaround
 
I devised a way to get around the virtual method call in the constructor by adding an argument to my base constructor which fixed
that issue. But getting around the virtual method call in my destructor is painful.
 
Lynn
Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Mar 17 11:52PM

> weaknesses also. G-d knows that I'm often a mess of pride,
> lust and apathy. I'm paraphrasing something there from
> the band switchfoot -- www.switchfoot.com .
 
If you honestly think that Noah actually existed and the flood actually
happened then you are beyond help mate.
 
/Flibble
Juha Nieminen <nospam@thanks.invalid>: Mar 18 10:17AM

> Depression and isolation are nothing
> new to the prophets and other biblical figures or to followers
> of Yeshua.
 
You are deliberately seeking for antipathy and hatred with your
holier-than-thou attitude. You are self-victimizing. You revel
in the backlash. It makes you feel virtuous and holy. It makes
you feel special.
 
You are deluding yourself, and deliberately making yourself an
insufferable, annoying person. You are deliberately making people
detest you. And for what? Do you honestly think you are receiving
some kind of "heaven points" by doing that? You do honestly think
that your "salvation" is dependent on you ostracizing yourself and
annoying other people? Do you honestly think that your god will
like you more when you make people hate you? Do you honestly think
that your god wants you to be a self-imposed martyr?
 
--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
David Brown <david.brown@hesbynett.no>: Mar 18 11:19AM +0100

> righteousness. Noah's preaching wasn't very successful
> in terms of persuading people. Noah is faulted by some
> of the sages:
 
Suppose we assume for a moment that Noah existed, spend 120 years
building the ark, etc., as though the Bible story was precise, literal
and accurate history (and that is a /huge/ assumption, which very few
people, even amongst dedicated Jews or Christians, actually believe).
 
You are comparing yourself to Noah, and your "C++ Middleware C++ Writer"
to the ark. The ark was what saved the entire human race, and every
animal species on the planet, from being completely wiped out by God's
fit of anger. Your project generates code to store C++ objects in
files. With a quick googling, I could not find a single reference to
the project that was not directly from you. Now, it may be a fine piece
of code, and it may be useful to some people - but you are /not/ saving
the world or the human race.
 
So don't you think your comparison here is just a little bit
unreasonable - perhaps a touch on the megalomaniac side?
 
 
Oh, and being bad at proselytizing and preaching is not something to be
proud of. Some people are good at that sort of thing, others are bad.
You are bad - your religious posts will do more to chase away potential
converts than to help win them to your side. So if you truly believe in
your God, and truly believe that /everyone/ should also believe as you
do, then please do the right thing - keep quite about it in a newsgroup
like this. And if anyone asks you for information, point them in the
direction of the nearest church, preacher, website, etc., and then keep
quiet.
 
But if you are in fact the devil in disguise, then maybe you want to
continue to show people that religion turns your brain to mush, forces
you to accept the blatantly impossible, and destroys your social skills.
Melzzzzz <mel@zzzzz.com>: Mar 18 01:17PM +0100

On 3/18/16 11:19 AM, David Brown wrote:
>> righteousness. Noah's preaching wasn't very successful
>> in terms of persuading people. Noah is faulted by some
>> of the sages:
 
...
 
 
> You are comparing yourself to Noah, and your "C++ Middleware C++ Writer"
> to the ark.
 
No need to bash him. Post is harmless...
Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Mar 18 04:32PM

On 18/03/2016 12:17, Melzzzzz wrote:
 
>> You are comparing yourself to Noah, and your "C++ Middleware C++ Writer"
>> to the ark.
 
> No need to bash him. Post is harmless...
 
Coding needs to be an inclusive and, ideally, a mathematically and
scientifically sound activity which means it should also be a secular
activity. There are plenty of religiously themed newsgroups or Facebook
to post religious bollocks to.
 
/Flibble
woodbrian77@gmail.com: Mar 18 11:34AM -0700

On Friday, March 18, 2016 at 5:17:09 AM UTC-5, Juha Nieminen wrote:
> holier-than-thou attitude. You are self-victimizing. You revel
> in the backlash. It makes you feel virtuous and holy. It makes
> you feel special.
 
Years ago I worked at IBM, American Express and
Southwest Airlines. This was before they drifted
away from the biblical understanding of marriage.
In the 1990s I saw some of the junk that was coming
down the pike so I started a company to escape from
being compelled to contribute to things I think are
wrong. Religious liberty is worth dying for.
Remember the Alamo? (I don't think you are an American,
but you can look it up if you want.)
 
I started the company because my back was against the
wall. Like the Israelites who were pursued by Pharoah,
my only option was to trust G-d. That was in 1999.
Since then G-d has helped me to build the company.
 
> annoying other people? Do you honestly think that your god will
> like you more when you make people hate you? Do you honestly think
> that your god wants you to be a self-imposed martyr?
 
Consider these verses:
 
"He was despised and forsaken of men, A man of sorrows
and acquainted with grief; And like one from whom men
hide their face He was despised, and we did not esteem
Him. Surely our griefs He Himself bore, And our sorrows
He carried; Yet we ourselves esteemed Him stricken,
Smitten of G-d, and afflicted." Isaiah 53:3,4
 
Many Bible believers, including myself, think those
verses describe Yeshua/Jesus. At any rate, there's
this example of a man who was rejected and considered
to be a fool. "He played the fool and He opened our
eyes." After Yeshua there was Paul. Paul was very
blunt and not afraid to express himself. Some hated
Paul and others loved him. I'm with those who loved
him.
 
What my views boil down to is that the ideal
situation for children is to have a father and a
mother. The diversity of a marriage with a man
and a woman makes it strong. For example, what
good are breasts that aren't producing milk to a
baby? But breasts that are producing milk, due
to a pregnancy, work great.
 
See also
 
www.dailywire.com
www.dennisprager.com
http://pragertopia.com/
www.onenewsnow.com
 
for further defense of my views.
 
Brian
Ebenezer Enterprises - "In fact, everyone who wants to
live a G-dly life in Messiah Yeshua (Jesus) will be
persecuted" 2nd Timothy 3:12
 
http://webEbenezer.net
Cholo Lennon <chololennon@hotmail.com>: Mar 18 04:29PM -0300

> http://pragertopia.com/
> www.onenewsnow.com
 
> for further defense of my views.
 
Why can't you understand that this is a group about C++, not a religion
one? We don't want your religious views here! Why you preach about your
beliefs in every post? I am sick and tired of you. I am agnostic, can
you respect that? Although I don't like religions, I always respect all
religious people, but there is a limit, this is the limit. The old
saying "your rights end where mine begin" is applicable here. You are
sick man, really sick, your head is not working. You are a fanatical, a
bigot.
 
Let's talk about programming, yes?
 
 
--
Cholo Lennon
Bs.As.
ARG
scott@slp53.sl.home (Scott Lurndal): Mar 18 07:54PM

>> in the backlash. It makes you feel virtuous and holy. It makes
>> you feel special.
 
>Years ago I worked at IBM, American Express and
 
Why do you think anyone in comp.lang.c++ gives a shit?
Gareth Owen <gwowen@gmail.com>: Mar 18 08:08PM

> Israelites who were pursued by Pharoah, my only option was to trust
> G-d. That was in 1999. Since then G-d has helped me to build the
> company.
 
IBM, American Express and Southwest Airlines have a combined operating
income of $26 billion. It seems that God has helped them a lot more.
 
Could it be that not being a judgmental asshole is more pleasing to God?
woodbrian77@gmail.com: Mar 18 02:59PM -0700

On Friday, March 18, 2016 at 3:08:40 PM UTC-5, gwowen wrote:
 
> IBM, American Express and Southwest Airlines have a combined operating
> income of $26 billion. It seems that God has helped them a lot more.
 
David against Goliath.
 
> Could it be that not being a judgmental asshole is more pleasing to God?
 
If speaking up for babies and children is being
judgmental, so be it.
 
 
Brian
Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Mar 18 10:02PM


>> Could it be that not being a judgmental asshole is more pleasing to God?
 
> If speaking up for babies and children is being
> judgmental, so be it.
 
Ah thanks for reminding us that not only are you a religious bigot you
are a homophobic misogynist religious bigot.
 
You failed to answer my earlier question Brian: God has cuntflaps
doesn't she?
 
/Flibble
woodbrian77@gmail.com: Mar 18 03:11PM -0700

On Friday, March 18, 2016 at 5:02:22 PM UTC-5, Mr Flibble wrote:
 
Leigh, you are an anti-religious bigot.
 
 
Brian
Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Mar 18 10:16PM

> On Friday, March 18, 2016 at 5:02:22 PM UTC-5, Mr Flibble wrote:
 
> Leigh, you are an anti-religious bigot.
 
Being anti-religious isn't bigoted because being anti-religion isn't
unreasonable mate.
 
/Flibble
Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid>: Mar 18 11:04AM +0100

> { double x; bool ok; do
> { if( ::std::cin >> x ) ...
 
> . It compiles fine.
[...]
 
> error: cannot convert
> 'std::basic_istream<char>::__istream_type {aka
> std::basic_istream<char>}' to 'bool' in assignment
 
"if ( bool ok = ... )" compiles fine.
"if ( ok = bool(...) )" compiles fine.
 
Before C++11 there was no operator bool() (it was operator void*())
Since C++11 it is "explicit operator bool()"
 
Regarding conditions for if statements, (N4296, 6.4§3) says:
 
"The value of a condition that is an initialized declaration in a
statement other than a switch statement is the value of the declared
variable contextually converted to bool (Clause 4). [...] The value of a
condition that is an expression is the value of the expression,
contextually converted to bool for statements other than switch [...]"
 
Then, (6.4§5) says: "If a condition can be syntactically resolved as
either an expression or the declaration of a block-scope name, it is
interpreted as a declaration."
 
So "if ( bool ok = cin>>x )" (an initialized declaration) and
"if ( cin>>x )" (an expression, interpreted as a declaration) are
treated the same, and both match the requirements of an explicit
constructor. (I would call the latter an "implicitly explicit
construction" :-)
 
In contrast, "if ( ok = cin>>x )" tries to do two things:
1) evaluate cin>>x (returning an istream&)
2) assign to a bool
The assignment fails, because it requires a conversion that is not
explicit. Making it explicit (ok = bool(cin>>x)) solves the problem, as
noted above. There is no need for an "if" statement to exhibit the
problem:
 
ok = cin>>x;
 
fails to compile as well.
 
My conclusion is that the explicit qualifier on "istream::operator bool()"
is the cause of the error.
 
Does that sound plausible? Thanks for the example.
 
-- Alain.
"Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com>: Mar 18 06:38PM +0100

On 18.03.2016 05:04, Stefan Ram wrote:
> { if( ::std::cin >> x ) ...
 
> . It compiles fine. I used to believe that »::std::cin >> x«
> was being evaluated in some kind of »boolean context«.
 
It is, it is a /condition/.
 
 
 
> int main()
> { double x; bool ok; do
> { if( ok = ::std::cin >> x )...
 
Now it's the complete assignment expression that is a /condition/.
 
The invocation of >> is not.
 
 
> std::basic_istream<char>}' to 'bool' in assignment
 
> . Why can't he (gcc 5.1.1 -std=c++17) convert it (::std::cin
> >> x) to bool anymore?
 
Because from C++11 and onward the conversion is an `explicit` `operator
bool`, which [1]can only be invoked implicitly for a /condition/.
 
With C++03 it was however just an implicit conversion to `void*`, so
with C++03 the code should compile.
 
Maybe you can test that by using `-std=c++03`.
 
• • •
 
Silly thing: the choice expression in a `switch` is also a /condition/.
 
 
Cheers & hth.,
 
- Alf
 
Notes:
[1] Instead of using a cast or a bang-bang, I would write `not (cin >>
x).fail()`). It's more verbose but far more clear. Explicit = good. :)
Zeljko Radicevic <zeljko.radicevc@gmail.com>: Mar 18 09:14AM +0100

On 03/17/2016 05:50 PM, red floyd wrote:
>> programming languange?
 
>> I'm looking for some simple example
 
> 1. There is no such language as C/C++. There is C, and there is C++.
for me it does not matter in which the programming language C or C ++ is
written, it is important to do their job, so I wrote the C/C ++
 
> 2. The ISO standard for C++ does not mention "file/folder ACLs". What
> you are looking for is a newsgroup with either "linux" or "unix"
> in its name.
 
Thank you
ram@zedat.fu-berlin.de (Stefan Ram): Mar 18 04:04AM

I have this program:
 
#include <iostream>
#include <ostream>
#include <istream>
 
int main()
{ double x; bool ok; do
{ if( ::std::cin >> x ) ...
 
. It compiles fine. I used to believe that »::std::cin >> x«
was being evaluated in some kind of »boolean context«. So I
tried this slight modification, inserting »ok = «.
 
#include <iostream>
#include <ostream>
#include <istream>
#include <limits>
 
int main()
{ double x; bool ok; do
{ if( ok = ::std::cin >> x )...
 
But now I get this message:
 
error: cannot convert
'std::basic_istream<char>::__istream_type {aka
std::basic_istream<char>}' to 'bool' in assignment
 
. Why can't he (gcc 5.1.1 -std=c++17) convert it (::std::cin
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