Saturday, October 27, 2018

Digest for comp.lang.c++@googlegroups.com - 19 updates in 7 topics

Horizon68 <horizon@horizon.com>: Oct 27 10:42AM -0700

Hello,
 
 
About my Good random number generators and scalability..
 
I think my mersenne and splitmix64 random generators can work
with multiple threads and can be "scalable", look at at
ThreadedRandomizedSeed() method to obtain a random seed:
 
==
 
function TMersenne.ThreadedRandomizedSeed():longword;
var a:double;
begin
if bool1=false
then
begin
bool1:=true;
a:=sin(GetCurrentThreadId)*high(longword);
if a < 0 then a:=-a;
if not assigned(mersenne1) then mersenne1:=TMersenne.create;
mersenne1.initialize(round(a));
result:=mersenne1.urand;
end
else result:=mersenne1.urand;
 
end;
 
==
 
You can create a mersenne or splitmix64 object for every
thread and initialize in each thread with ThreadedRandomizedSeed(), and
after than get your random number in each thread, i think this way is
"scalable".
 
 
My Good random number generators for Delphi and FreePascal
was updated to version 1.01, you can port them to C++..
 
Look at them they are powerful.
 
Author: Amine Moulay Ramdane that has enhanced
both random number generators.
 
Description:
 
This is an enhanced versions of both Mersenne Twister that is a
good random number generator and Splitmix64 that is a fast random number
generator, both have passed the BigCrush tests.
 
Look into defines.inc file, there is many options:
 
{$DEFINE CPU32} and {$DEFINE Windows32} for 32 bit systems
 
{$DEFINE CPU64} and {$DEFINE Windows64} for 64 bit systems
 
Look at test.pas demo inside the zip file...
 
You can download it from:
 
https://sites.google.com/site/scalable68/good-random-number-generators
 
Language: FPC Pascal v2.2.0+ / Delphi 5+: http://www.freepascal.org/
 
Operating Systems: Win , Linux and Mac (x86).
 
Required FPC switches: -O3 -Sd
 
-Sd for delphi mode....
 
Required Delphi switches: -$O+
 
 
 
Thank you,
Amine Moulay Ramdane.
"Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid>: Oct 27 03:09PM -0700

On 10/27/2018 10:42 AM, Horizon68 wrote:
> begin
> bool1:=true;
> a:=sin(GetCurrentThreadId)*high(longword);
 
Partitioning wrt angle as thread id...
 
[...]
Paul <pepstein5@gmail.com>: Oct 27 01:16PM -0700

On Tuesday, October 2, 2018 at 7:56:08 PM UTC+1, David Brown wrote:
 
> Marvellous. Keep asking questions, and keep learning. That's what this
> newsgroup is for (despite appearances sometimes).
 
> Once you have had a try, post your code if you are not sure about it.
 
Thanks for your encouragement.
I am actually looking for a C++ tutor, by the way, for online sessions
via something like Google hangout.
 
If anyone is interested, please reply to author and we can discuss rates
and availability.
 
I drafted a new topic with this tutoring request, but I thought I might
get in trouble on OT grounds.
 
I know there are standard websites for tutoring but I think the advice
here is far more expert than what I would get from a tutoring website.
 
Thanks,
 
Paul
Elephant Man <conanospamic@gmail.com>: Oct 27 07:19PM

Article d'annulation émis par un modérateur JNTP via Nemo.
tomusatov@gmail.com: Oct 27 06:21AM -0700

I am wondering if C++ would be the best language to write a program allowing:
 
1. Highlight some text
2. Ctl+HOTKEY1 stores the string of text somewhere as COPIEDTEXT1
3. Highlight another string of text
4. Ctl+HOTKEY1 stores another string of text somewhere as COPIEDTEXT2
 
THEN
 
5. Ctl+HOTKEY2 pastes COPIEDTEXT1
6. Ctl+HOTKEY2 pastes COPIEDTEXT2
 
Can someone point me in the right direction?
 
Thanks,
 
Musatov
"Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com>: Oct 27 03:32PM +0200


> 5. Ctl+HOTKEY2 pastes COPIEDTEXT1
> 6. Ctl+HOTKEY2 pastes COPIEDTEXT2
 
> Can someone point me in the right direction?
 
You /can/ do it in C++.
 
Depending on the system you want to do this for, some other language
will probably be less work.
 
Right direction pointer: when Microsoft replaced the original Windows
clipboard viewer with one supporting multiple clips, like you sketch,
that marked the end of having a standard clipboard viewer in Windows.
The clipboard relies on simplicity for it to be useful. Adding
complexity and hidden modes is therefore not a good direction.
 
 
Cheers & hth.,
 
- Alf
Luuk <luuk@invalid.lan>: Oct 27 03:38PM +0200


> Can someone point me in the right direction?
 
> Thanks,
 
> Musatov
 
In Windows 10 (from build 1809) you can view your copies with Windows+V.
 
CTRL+C copies (and adds to the list)
CTRL+V pastes
Windows+V (shows the list)
 
Now one has to wait till 1809 get released...
Sam <sam@email-scan.com>: Oct 27 10:02AM -0400


> 5. Ctl+HOTKEY2 pastes COPIEDTEXT1
> 6. Ctl+HOTKEY2 pastes COPIEDTEXT2
 
> Can someone point me in the right direction?
 
The right direction for you would be some general books on computer
programming, where you will learn that in the several thousand of terse,
single-spaced pages that make up the current C++ standard, there is no
mention whatsoever about "highlighting" text, in some mysterious fashion, or
equally-mysterious "hotkeys", that do wondrous things.
 
This is purely a function of your operating system, and the exact task for
implementing these kinds of things depend entirely on the operating system
being used.
 
Since you don't even realize that this is an operating system-specific
question, and you didn't specify which OS you're using, I think it would be
rather difficult, if not impossible, for you to implement the task at hand
right now; but maybe several years down the road.
 
It just so happens that last week I finished implementing copy/cut/paste
support in my X toolkit library (shameless plug:
https://www.libcxx.org/w/copycutpastemenu.html). I don't remember exactly
when I started it, but I've been working on this library for the last eight
years, and coding C++ for …much longer than that. Just to give you a rough
idea how complicated C++-related things are, in the real world.
 
The only other thing I can tell you with some level of confidence is that,
whatever operating system you're using, it's unlikely that you will be able
to modify its default copy/cut/paste behavior in the manner you desire. All
traditional OSrd implement copy/cut/paste internally, behind the scenes, and
their exact mechanics are not exposed to applications. The mouse pointer
operations and/or the keyboard shortcuts for copy/cut/pasting text get
processed entirely by the operating system, or the GUI library being used on
your operating system. The application does not even realize that this is
happening. The OS/GUI library handles the mechanics of this process entirely
on its own. All that the application does is put up text input fields, where
text gets typed in when that text input field has keyboard focus, and the OS
or the GUI library handles copy/cut/paste operations on its own. All the
application cares about is text that mysterious appears in its
aforementioned text input fields, and how it got there, it doesn't really
care.
 
Some OSes might offer third-party add-on tools that enhance the existing
copy/cut/paste behavior. Those tools typically use highly OS-specific
internal functions to modify its copy/cut/paste behavior.
Manfred <noname@add.invalid>: Oct 27 06:41PM +0200

On 10/27/2018 4:02 PM, Sam wrote:
> question, and you didn't specify which OS you're using, I think it would
> be rather difficult, if not impossible, for you to implement the task at
> hand right now; but maybe several years down the road.
The above sounds excessively hard on the poor OP.
 
> last eight years, and coding C++ for …much longer than that. Just to
> give you a rough idea how complicated C++-related things are, in the
> real world.
It is true that C++ is a complex language, but in this case (copy/paste
of strings) the complexity is not about usage of the language, instead
it is mainly about how to interface with the OS - or better, how to
interface with whatever GUI manager is offered by the target platform.
Even this part, however, is not complex in the sense that it be rocket
science. Most of the work would be finding and digging through the
documentation of the system API, the patterns used throughout it, and
such API's are usually very large.
 
> for copy/cut/pasting text get processed entirely by the operating
> system, or the GUI library being used on your operating system. The
> application does not even realize that this is happening.
It is true that it would be impossible or next to impossible to modify
the system clipboard behavior.
It is instead possible to override the relevant commands and implement
your own clipboard scheme. Obviously this would only work within your
own applications.
Again, this is not a C++ problem, it is GUI software development instead.
 
 
The OS/GUI
tomusatov@gmail.com: Oct 27 11:54AM -0700

On Saturday, October 27, 2018 at 8:38:46 AM UTC-5, Luuk wrote:
> CTRL+V pastes
> Windows+V (shows the list)
 
> Now one has to wait till 1809 get released...
 
Bout time. Amen!
Paul <pepstein5@gmail.com>: Oct 27 02:19AM -0700

Below, I will post a question that I would like some help with (if possible).
The best type of help would be something like "Think about using..." rather
than just giving the answer. I would like to avoid using post-C++11 features
if possible.
People sometimes get (rightly) homework-suspicious when they see posts
like these. This question is for self-study purposes only. I am not
a student, and am not enrolled in any course. It is also not part of
any external evaluation process or interview process.
The source of the original question is
https://www.testdome.com/questions/cpp/multiple-choice-test/9808?visibility=1&skillId=7
 
I have tried the very basic solution of using delete[] in the destructor
without using smart pointers. That is not the intended solution.
I tried using unique pointers with release(). This compiled but was also
not the intended solution. reset() wasn't what they wanted either.
 
Many thanks for your help,
 
Paul
 
// CODE BELOW
/*Multiple choice test has several multiple choice questions. Each question can have only one correct answer. Additionally, timed multiple choice test can specify the time allowed for solving each question in the test.
 
The code below satisfies this specification, but the customer complained that the memory usage of the program constantly increases. Fix this problem.*/
 
#include <iostream>
#include <string>
 
class MultipleChoiceTest
{
public:
MultipleChoiceTest(int questionsCount)
{
this->questionsCount = questionsCount;
answers = new int[questionsCount];
for (int i = 0; i < questionsCount; i++)
{
answers[i] = -1;
}
}
 
void setAnswer(int questionIndex, int answer)
{
answers[questionIndex] = answer;
}
 
int getAnswer(int questionIndex) const
{
return answers[questionIndex];
}
 
protected:
int questionsCount;
 
private:
int* answers;
};
 
class TimedMultipleChoiceTest : public MultipleChoiceTest
{
public:
TimedMultipleChoiceTest(int questionsCount)
: MultipleChoiceTest(questionsCount)
{
times = new int[questionsCount];
for (int i = 0; i < questionsCount; i++)
{
times[i] = 0;
}
}
 
void setTime(int questionIndex, int time)
{
times[questionIndex] = time;
}
 
int getTime(int questionIndex) const
{
return times[questionIndex];
}
 
private:
int* times;
};
 
#ifndef RunTests
void executeTest()
{
MultipleChoiceTest test(5);
for (int i = 0; i < 5; i++)
{
test.setAnswer(i, i);
}
 
for (int i = 0; i < 5; i++)
{
std::cout << "Question " << i + 1 << ", correct answer: " << test.getAnswer(i) << "\n";
}
}
 
int main()
{
for (int i = 0; i < 3; i++)
{
std::cout << "Test: " << i + 1 << "\n";
executeTest();
}
}
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