Comments by Greg Utas

Greg Utas 19-Nov-23 11:26am View

You haven't told us what the code is supposed to do. To see if it's correct, you should run it and test it. After all, you are the one who knows what it's supposed to do.

Greg Utas 28-Oct-23 15:08pm View

I interpret the question to mean that there is virtual memory space with addresses 0 to 489 (490 words) and 3 physical pages that hold 100 words each. Each of the physical pages could hold virtual addresses 0-99, 100-199, 200-299, 300-399, or 400-489. It's not page 480, page 315, and so on that are being accessed, but virtual memory addresses 480, 315, and so on.

Greg Utas 27-May-23 19:54pm View

Cat got your keyboard? LOL.

Greg Utas 6-May-23 14:32pm View

This is not a code-to-order service. At the very least, you'd have to show what you've done so far. Keep in mind that for anyone to help with this, they have to be familiar with, or be willing to familiarize themselves with, Boost's logger classes. And all of this strikes me as a fair bit of work.

Greg Utas 31-Oct-22 9:32am View

Check your code. Is it really what you've posted? For one thing, you have an extra } in there. Your first printf looks correct to me. But I've only used the C++ version (std::cout).

Greg Utas 31-Oct-22 9:17am View

It's printf, not print.

Greg Utas 30-Oct-22 21:24pm View

The sad fact of the matter is that no one here will do your assignment for you unless you have shown some code that makes a reasonable attempt at it. This is not a trivial assignment, so you must have a reasonable amount of experience reading specifications and developing software if you are expected to undertake it. So give it a try.

Greg Utas 30-Oct-22 9:56am View

I went straight to C++, bypassing C, so I don't know much about printf. But I'd surprised if the compiler analyzed the string argument to printf to see if the variadic argument list was too short or contained the wrong types. I'd expect that to show up at run-time, as error messages from printf itself.

Greg Utas 27-Oct-22 8:20am View

Some obscure site has better documentation than MSFT? LOL.

Greg Utas 16-Oct-22 7:58am View

The project that was cancelled. :)

Greg Utas 14-Oct-22 9:45am View

The fragment looks OK, so you're going to have to show more code than this. The error is elsewhere.

Greg Utas 12-Oct-22 10:16am View

Not only that, but from what I can tell you have to use .type() to look at the actual type so that you can any_cast to the correct type. A dog's breakfast unless the set of types to be supported is small and unlikely to grow.

Greg Utas 11-Oct-22 8:57am View

A 5 for you regardless! I hadn't heard of it. It appears to simply reduce boilerplate (the more verbose template function version) without actually providing anything new.

Greg Utas 10-Oct-22 9:47am View

It doesn't compile for me in C++17, for the same reason given by merano99 ("auto not allowed here"). It's actually C++20. C++11 only had auto variables and return types.

Greg Utas 10-Oct-22 9:35am View

That's a 5.

Greg Utas 7-Oct-22 15:27pm View

Then it's a right-angle triangle, not an isosceles.

Greg Utas 7-Oct-22 11:02am View

Looks good. Thanks.

Greg Utas 7-Oct-22 10:32am View

Sorry to be a pain, but you should edit your question and append the code there.

Greg Utas 7-Oct-22 10:20am View

You need to show your existing code, not just the problem statement. Without it, people will assume that you may have done nothing, because we get "write this code from scratch" questions all the time.

Greg Utas 24-Sep-22 13:40pm View

Rust is different from most languages. I use C++ and looked at Rust out of curiosity but didn't want to go down what looked like a rabbit hole. But I'm retired, whereas you seem to be closer to starting out, and becoming proficient at Rust could be a very good decision from the standpoint of job opportunities going forward.

When I looked at Rust, there seemed to be some good books about it, so I would suggest that you read them and do whatever exercises they contain. I would pay special attention to how they suggest implementing an object-oriented design in Rust, because it doesn't have objects. However, I believe that a large system--meaning one where architecture is important--must provide frameworks. Classes are a good way to do that, and if a language doesn't have them, it had better have something that compares. I got the sense that Rust allowed you to define the equivalent of Java interfaces, but that was around the point that I decided not to dig any deeper.

Greg Utas 23-Sep-22 15:20pm View

You're allocating an array in the second constructor. I've done that with unique_ptr<T[]>, but the first answer to this post says that it's not a good idea for shared_ptr:
https://stackoverflow.com/questions/39142343/wrap-dynamic-array-with-shared-ptr-by-make-shared

And here's another post:
https://stackoverflow.com/questions/13794447/can-you-allocate-an-array-with-something-equivalent-to-make-shared

Greg Utas 23-Sep-22 15:14pm View

What is the type of T in the second constructor? T is a parameter to the third constructor but not the second.

Greg Utas 21-Sep-22 16:10pm View

The one here is the duplicate. Don't worry about it.

Greg Utas 21-Sep-22 15:32pm View

Your question somehow got posted twice. Since both were posted at the same time, it probably happened by accident. But some people do this when they don't get an answer quickly, and that's frowned upon. This version of your question might get flagged as a repost, in which case it will be deleted.

Greg Utas 20-Sep-22 20:31pm View

Sure, but it depends on the numbers involved. Multiplying by 1/n is the same as dividing by n.

Greg Utas 14-Sep-22 17:28pm View

I haven't used this library, but you should try stepping through this code with a debugger to see if any surprises show up. And I'm fairly certain that all of the socket functions return something which indicates success, failure, or how many bytes were sent or received. You should be checking all of those results and writing warnings to the console if anything unexpected occurs. And since this is TCP, it's possible (although unlikely) that a space causes the previous characters to be sent. Don't forget that there is no such thing as a "complete message" in TCP: when you invoke send, the contents can get split into multiple packets or buffered and combined into a larger packet.

Greg Utas 12-Sep-22 8:20am View

I, and probably many others, don't even know what the "snake game" is. Second, this is a fair bit of code, and you're asking us to debug it for you. Once you're writing software of this size, you absolutely must learn to use a debugger. It's almost inevitable that code this size will have bugs, and by far the fastest way to find them is to step through the code with a debugger, line by line, to see where its behavior differs from what you expected.

Greg Utas 11-Sep-22 14:02pm View

This isn't a "do my assignment" site. But even if it were, the question does not provide enough information to write a program.

Greg Utas 9-Sep-22 15:20pm View

Show us your code.

Greg Utas 7-Sep-22 9:47am View

I rarely look at what's coming in C++2X, because most of it is clutter in my opinion. But I doubt it, because if you want to manipulate an object's private data, you're supposed to use that object's functions, not some backdoor approach.

Greg Utas 7-Sep-22 9:32am View

You are using std::span to change the private data of a std::string, which tracks the length of its string. There is simply no way to update that length when you fiddle with the string's characters. A span is only a subset of an array and has no knowledge of any object that manages that array.

Greg Utas 6-Sep-22 14:28pm View

What you have "tried" so far isn't remotely close to a reasonable attempt at this exercise. If this is an assignment that you have been given, you should be able to produce much more than this. If you can't, you have a lot of catching up to do.

Greg Utas 2-Sep-22 7:24am View

Deleted

The easiest way to avoid empty strings in the vector is not to put them there in the first place:

while(getline(sjp2,s))
{
if(!s.empty() && (s.back() == '\r')) s.pop_back();
if(!s.empty()) L2.push_back(s);
}

That pop_back line is n case the file you're reading was created on Windows but is being read on Linux. Windows puts a "\r\n" at the end of a line, whereas Linux only uses "\n". It is therefore necessary to strip out the '\r'. You can remove that line unless you need to handle that scenario.

Greg Utas 1-Sep-22 15:07pm View

The moderators don't like questions being deleted. I provided an answer saying that the template arguments had to be provided explicitly, so the question and answer might help someone else with the same problem.

Greg Utas 1-Sep-22 14:48pm View

My mistake. There is a "Have a Question or Comment?" button for Solution 1 that can be used. The site does not want an OP to post a Solution to their own Question. Just edit the Question instead. Besides, your Solution isn't anywhere near a solution.

Greg Utas 1-Sep-22 8:19am View

To reply to a Solution, please use the "Reply" button instead of posting a new "Solution".

Greg Utas 31-Aug-22 12:41pm View

It looks like it should be model1 instead of i.

Greg Utas 31-Aug-22 10:45am View

I don't think you're notified when a solution is updated, so please see my revised version.

Greg Utas 31-Aug-22 9:16am View

It was commented out in the question.

Greg Utas 30-Aug-22 8:25am View

Where are lines 30 to 38? The code fragment doesn't even have that many lines. And the 2-digit case is trivial. num % 11 finds the remainder (modulo) of num when divided by 11. If it's 0, then num is evenly divisible by 11.

Greg Utas 30-Aug-22 8:07am View

Your code ends somewhere in the middle. The fragment that you provided only handles 2-digit numbers, and it's unclear whether it handles a 1-digit number correctly.

Greg Utas 26-Aug-22 7:58am View

In order to get any help, you will have to show some work. This is not a "write this code for me" site.

Greg Utas 23-Aug-22 10:47am View

Test overrides IA::Test and IB::Test simultaneously. Defining functions with the same name in base classes that will be multiply inherited seems dubious to me, but maybe there are legitimate examples.

Greg Utas 22-Aug-22 16:57pm View

The types uintptr_t, intptr_t, and size_t should be the same size as a pointer on the underlying platform.

Greg Utas 22-Aug-22 12:11pm View

I only use static libraries, not DLLs, so I'm not really the one to answer this question. I believe that the DLL will be mapped into your process's address space, but where? You wouldn't be able to hard-code the address, but you might be able to get it from an interface that the DLL provides. Here is a link that I found:

https://docs.microsoft.com/en-us/windows/win32/dlls/using-shared-memory-in-a-dynamic-link-library

Greg Utas 22-Aug-22 6:09am View

Sure, it's impossible to lose if it's thoroughly tested. But there isn't any guarantee of making gains either. If you sell XAUUSD at 1791 and buy it back at 1790, it can still go down. And if your spreads are that tight, commissions will also eat into your gains.

Greg Utas 21-Aug-22 6:58am View

I changed the tag to C#.

Greg Utas 18-Aug-22 20:55pm View

You're welcome. But like some of the other answers suggested, learn to use the debugger. It is the only way to find problems in more complicated software, so it's a critical skill that every developer must learn.

Greg Utas 18-Aug-22 9:06am View

I know what you're talking about (apart from the specific reference to ToS) but have never tried to develop this kind of software. My guess is that your computer has to generate the studies based on the feed of trades. If you don't want to write that software yourself, you'd have to look for an open-source version on GitHub or wherever.

EDIT: I will revise that from guessing to being certain. Even an SMA, for example, has a vast number of timeframes, and there's no way any system is going to feed updated results for each of them.

Greg Utas 16-Aug-22 13:39pm View

I've never used it, but the page that Richard linked to should give you the answer.

Greg Utas 15-Aug-22 20:54pm View

I'm an opinionated bastard. :)

By the way, the site that Richard linked to below is the one I use when I need to look something up about C++ or C. It's much more of a reference site than a teaching site, however.

Greg Utas 12-Aug-22 15:44pm View

Is this what you've tried, and it doesn't work, or are you posting an answer to your own question?

Greg Utas 9-Aug-22 8:01am View

I don't understand the question either. Either you left out some information or it is poorly worded. I'm guessing that there is an example (an array) that is supposed to produce the output that you've shown.

Greg Utas 7-Aug-22 10:11am View

It is considered inappropriate to post an answer to your own question, let alone mark it accepted. Instead, update your question with more information. You also received three responses, none of which you upvoted or marked accepted. Posting your own answer and then accepting it can be interpreted as none of those answers being valid.

Greg Utas 7-Aug-22 7:47am View

This is not an Answer, so marking it as "accepted" is inappropriate. It is standard for exceptions to be derived from a limited set of base exception classes.

Greg Utas 7-Aug-22 6:32am View

The "user" of your library is the application writer.

It's not so much the severity of an error as whether it is expected. The network being unavailable, or the destination being unreachable, is something that can happen even if the code is correct, so these things shouldn't be exceptions. They would be handled with if and errno.

As a library writer, it's unlikely that you should be dealing with threads and signals. That's up to the caller of your library.

Greg Utas 6-Aug-22 19:53pm View

"For the scenario being executed" referred to whether the user's code is correct in a particular scenario. If it is, it shouldn't have to catch exceptions.

Stroustrup's statement still leaves the question of whether an error is severe enough to warrant an exception. When an exception occurs in a live system, you need debugging information to help reproduce the problem. Specifically, you want a stack trace, and getting one is expensive enough that you don't want exceptions to occur in released code. When one occurs, it should be treated as a bug, and the code fixed so that it no longer occurs. Neither the library nor the user's code should cause them during proper operation. There are times that if statements and errno are preferable.

I've written an article, Robust C++: Safety Net, which deals with recovering from exceptions. You might find it useful.

Greg Utas 6-Aug-22 17:51pm View

By correct code, I mean correct for the scenario being executed. That doesn't mean correct in every scenario.

Stroustrup's guideline still leaves the design question of what a function's signature should be. If it can be designed to report a failure without throwing an exception, by returning nullptr for example, that is preferable. Returning npos or cend() from find follows this rule. But functions like front or pop_back can't do anything other than thrown an exception if a vector is empty.

Greg Utas 6-Aug-22 13:38pm View

Exceptions are provided to report errors from which it is impossible to recover. If an exception occurs, it should almost always mean that the code needs to be fixed. Because of this, many programs don't bother to catch exceptions. They just exit and leave it to the designer to debug and fix the problem. But it depends on the type of application. A game would just continue from where it left off. A server would clean up the current transaction and go on to the next one. It's not a question of whether code can be proven to be correct. The point is that correct code shouldn't have to catch exceptions. The library should only throw one when it has no other way to report an error. If code catches exceptions, it is either because it wants to be resilient or improve the way that it reports serious errors.

Greg Utas 6-Aug-22 12:13pm View

True. But my point is that once the code is correct, it shouldn't be necessary to catch any exceptions. This is a good way to tell whether your library is throwing exceptions appropriately.

Greg Utas 31-Jul-22 20:00pm View

If you've learned to use a debugger, you've taken a very important step.

Yes, each variable serves a different purpose--too many of them! You need one variable for the user's password, whether the user enters it or you generate it, and a second variable when the user retypes the password. That's all. But you have FOUR of them: password, pass, P, and userp.

Greg Utas 31-Jul-22 19:57pm View

A random string is an error. I don't think the code does what you want it to.

Greg Utas 31-Jul-22 16:16pm View

I prefer parentheses to make things clear, but it's correct. In descending order, the priorities are - < ? =.

Greg Utas 31-Jul-22 13:16pm View

That function call looks like the only place that affects the underlying buffer, so maybe the problem is in its implementation.

Greg Utas 31-Jul-22 11:41am View

Is m_stream the underlying stream? If that's what's getting corrupted, the only place this code affects it is in its read call. It looks recursive but I'm guessing it has a different implementation because read is a virtual function.

And is your space bar broken or something?! :)

Greg Utas 30-Jul-22 8:29am View

5. LOL.

Greg Utas 30-Jul-22 7:06am View

You haven't told us what your project is, so you can't expect to get any suggestions. If you do decide to tell us, you'll have to provide some details. One or two sentences probably wouldn't be enough information.

Greg Utas 29-Jul-22 11:31am View

I'm sorry, but this isn't a code conversion service. You need to make an effort before anyone will help you.

Greg Utas 27-Jul-22 5:53am View

Definitely better.

Greg Utas 24-Jul-22 9:24am View

What problem have you faced with scanf? You haven't told us.

Greg Utas 23-Jul-22 8:56am View

Thanks. But even just reading the code, there are a lot of issues.

Greg Utas 23-Jul-22 8:50am View

The code is understandable, but anyone who wants to compile this in order to help you will have to strip out all the line numbers. Please remove them.

Greg Utas 19-Jul-22 7:30am View

If you know the derived class, use static_cast. It has the same syntax as the ones that CPallini showed but has no overhead (dynamic_cast does) and isn't overkill (like reinterpret_cast, which should be avoided when possible).

Greg Utas 14-Jul-22 16:40pm View

So how did your multithreaded server work out? That's how I would also do it, so I'm not sure what you're asking.

Greg Utas 30-Jun-22 14:40pm View

I like auto because it saves typing (especially when template iterators are involved) and it keeps lines under 80 characters, which is what I prefer. But it sounds like you're new to C++, so what you're doing makes a lot of sense.

Greg Utas 29-Jun-22 17:51pm View

The compiler knows what the function returns, so auto will match the underlying type exactly.

Greg Utas 29-Jun-22 15:57pm View

I love auto, and eventually you will too. The compiler never has a problem guessing the correct type, but you have to be explicit when you want a reference:

const string& f();auto str = f();

and str copies the string, which is more expensive than saving the reference. To save the reference, you have to write auto& str....

Greg Utas 29-Jun-22 15:55pm View

Deleted

I love auto, and eventually you will too. The compiler never has a problem guessing the correct type, but you have to be explicit when you want a reference:

const string& f();
auto str = f();

and str copies the string, which is more expensive than saving the reference. To save the reference, you have to write auto& str....

Greg Utas 29-Jun-22 7:39am View

Yes, that's what the compiler will do when it instantiates the template. You can probably get around it by wrapping each argument in a class that effectively acts as a union.

Greg Utas 28-Jun-22 23:19pm View

You're right. It's ~(-1), not ~0, that will be interpreted as false.

Greg Utas 28-Jun-22 18:38pm View

I think it actually means i != 0, which will have the same effect. What amazes me is that some C and C++ programmers think it's brilliant to save a few keystrokes, so they write crap like this.

Greg Utas 28-Jun-22 14:53pm View

See the discussion above. If you can only count the same product once, more code is needed.

Greg Utas 28-Jun-22 14:51pm View

That statement was unclear, so I chose to ignore it! I though it might mean not to check both i*j and j*i, which is what the second loop seemed to be aiming at. If only unique numbers are to be counted, then a set or array of bools would have to be used to avoid double-counting.

Greg Utas 28-Jun-22 10:33am View

It should increment odd once because i == j.

Greg Utas 28-Jun-22 10:21am View

In your second loop:

if(a[i][j] % 2 == 0)
{
   ++even;
   if(i != j) ++even;
}
else
{
   ++odd;
   if(i != j) ++odd;
}

A different way to approach this is not to write any code at all. The product of two even numbers, or an even and an odd number, is an even number. The product of two odd numbers is an odd number. The multiplications are 1...10 x 1..10, so there are 5 odd numbers in each range. You should therefore expect 25 odd numbers and 75 even numbers.

Greg Utas 25-Jun-22 12:16pm View

Well done! You have learned one of the most important skills that a developer needs.

Greg Utas 21-Jun-22 11:29am View

5. And then the number of users of the pointer would be decremented when it was erased.

Greg Utas 15-Jun-22 6:44am View

I tried that as the first thing in my main but still the same result.

On an unrelated(?) topic, I have a test that kills a runaway thread with ctrl-C. It works on Windows but not on WSL2/Ubuntu. There is no sign of the ctrl-C getting forwarded to the Linux Console Window that VS2022 creates as a tab.

Greg Utas 15-Jun-22 5:59am View

Curious.

Greg Utas 14-Jun-22 19:48pm View

Each of your comments resulted in me getting 2 emails and 2 little red box notifications.

Greg Utas 11-Jun-22 17:29pm View

That was fast!

Greg Utas 11-Jun-22 9:43am View

What do you mean by "tracking"? An inventory of vehicles and their assignments? Or their current location, updated in real time? Something else?

Greg Utas 9-Jun-22 12:03pm View

I'd argue that insertion sort requires an array. But you've got a good point with tree sort.

Greg Utas 8-Jun-22 17:27pm View

Given that you have deleted your original question and entered a completely new one, my comment no longer makes sense. Do you realize how rude that is?

Greg Utas 5-Jun-22 7:41am View

If it's divisible by 100, it's not a leap year unless it's divisible by 400, in which case it is. 2000 was a leap year and will likely be encountered when running your program.

Greg Utas 3-Jun-22 17:43pm View

5. Thanks for the info. I'm going to proceed with the default priorities and see how things turn out. I think it has a good chance of working even without them.

Greg Utas 3-Jun-22 8:13am View

A real-time system needs priorities. A scheduler that doesn't have them is ill-suited to the purpose. It works fine on Windows. On Linux, privileges, not a lack of support, seems to be the problem.

Greg Utas 3-Jun-22 7:31am View

I'm not so concerned about the app's priority as the relative priority of the threads, and that looks like it's going to be difficult. See my recent comment to k5054 below.

Greg Utas 2-Jun-22 19:14pm View

It looks like there will be an issue with thread priorities:

https://man7.org/linux/man-pages/man7/sched.7.html states

For threads scheduled under one of the normal scheduling policies (SCHED_OTHER, SCHED_IDLE, SCHED_BATCH), sched_priority is not used in scheduling decisions (it must be specified as 0).

So unless SCHED_RR (or SCHED_FIFO) can be set, it looks like lowering some threads' priorities will have no effect, or that it may not even be allowed.

Greg Utas 2-Jun-22 18:56pm View

It can set various limits, but there isn't one for priority.

https://man7.org/linux/man-pages/man3/getrlimit.3p.html

EDIT: What's with this bunch? There's another page where the nice value can be changed:

https://man7.org/linux/man-pages/man2/getrlimit.2.html

Greg Utas 2-Jun-22 16:25pm View

Thanks. Never heard of it, but I'll look into it. This is the first time I'm using Linux.

Greg Utas 2-Jun-22 12:31pm View

Thank you for your detailed response. Lower the priorities?! That's a great idea. A deployment could then presumably use setcap to raise the process priority. It's the relative thread priorities that are the key in any case: if those are correct, then I basically control the rest of the scheduling anyway, so I think it will work.

I'll let you know how this works out. Maybe lowering the priority needs permission too. :)

Greg Utas 1-Jun-22 9:56am View

You're going to have a problem when you change this. You define marks[4] but then check i < 5. This will lead to using marks[4], which is out of bounds. The index for an array defined with [n] goes from 0 to n-1.

Greg Utas 29-May-22 19:33pm View

That's not passing references, but pointers. References would be int& sum and int& average.

Greg Utas 29-May-22 8:25am View

And should a projection of the line (a) bisect the hexagon through two vertices, (b) through two edges, (c) form one of the hexagon's sides, or (d) I don't care as long as it's a hexagon! Decisions, decisions. :)

Greg Utas 27-May-22 11:09am View

Grazie. I usually find those details when the compiler complains. :)

Greg Utas 27-May-22 8:03am View

Yes, this is unambiguous. But you could just stick to your original constructor, with its two defaults. The only difference is that your original code allows a ClassOne to be constructed with *one* argument (x), with y still defaulting to 0. I don't think that's a useful capability, or even appropriate, so I prefer your new version. But I wouldn't bother to forward from the ClassOne() constructor to the ClassOne(int, int) constructor. I'd just initialize x and y to 0 right in the ClassOne() constructor, which is more efficient.

Greg Utas 27-May-22 7:34am View

The reason that the ClassOne(int, int) constructor was selected is because both of its arguments specify 0 as a default. So if an instance of the class is declared without arguments for the constructor, that constructor will be selected. I think that if you actually declared a constructor that took no arguments, the compiler would generate an error saying that your code was ambiguous: it wouldn't know which constructor to select, because both could be invoked without arguments.

Greg Utas 26-May-22 14:17pm View

Kind of strange, because serial killers are always referred to using three names. :)

Greg Utas 26-May-22 10:40am View

PIEBALDconsult has flagged this member in the Spam & Abuse forum. The original post seems to have been edited but is still inappropriate, and your article has a second one from the same member. Please ignore the troll.

Greg Utas 26-May-22 6:57am View

It's very unlikely that you'll get any help unless you show some code that you wrote. This isn't a "please do my assignment" website.

Greg Utas 26-May-22 5:57am View

I hope somebody finds it useful. :)

Greg Utas 20-May-22 15:05pm View

It's unlikely you'll get any help unless you provide more details as to what error you're getting. A compile error? A link error? A run-time error? Or it just doesn't do what you want? At least you have comments that suggest you're working on a binary search tree, but that's all we know.

Greg Utas 18-May-22 9:58am View

Right you are. When I see an #include, I just assume. :)

Greg Utas 18-May-22 9:49am View

You tagged your "question"--I use the term loosely, because it's a request for us to write all the code for you--as Python, yet you've "tried" a C++ header?

Greg Utas 16-May-22 20:49pm View

I haven't used this requires is_same<> stuff, but I'm guessing that it shouldn't be repeated in the function definition. Also, if U is a parameter to that function, won't you have to give it name for the function to be useful?

Greg Utas 8-May-22 10:10am View

I doubt anyone will do this for you even if they wanted to. First, you haven't even told us what this game is. Second, how can a flowchart be placed in a comment?

Greg Utas 6-May-22 17:43pm View

Show us your code then.

Although I use C++, not Java, I doubt you need to use strings. If you divide an integer by 10 in C++, and I assume in Java, it is the equivalent of removing the last digit. It doesn't get rounded up, but truncated.

Greg Utas 6-May-22 15:02pm View

Maybe the software that initiates the scaling thinks that your jobs must be stateless, which is the mindless fashion these days.

Greg Utas 4-May-22 15:22pm View

If three nested loops are needed, why worry about it? There isn't much happening within each loop. Tools that generate metrics are hardly infallible.

That said, I don't know Go--which means that your code isn't "commented". If it was, I'd know what it was trying to do and might even be able to offer a useful suggestion. There are two brief comments, neither of which does much to explain the code. You're looking for matches in customer data using filters, and this requires a sort for some reason.

Greg Utas 4-May-22 13:33pm View

You're welcome.

Greg Utas 3-May-22 8:41am View

I don't know how to write these scripts, but the more information you provide, the better the chances of getting an answer.

Greg Utas 3-May-22 7:15am View

You have answered two of the questions. If 0 is included, the first argument will be n=0. The function will only call itself if n<=50. So how will it change n each time when it calls itself? You need to do this yourself. I don't think anyone here will just give you the solution. It would be unethical.

Greg Utas 2-May-22 18:43pm View

200 sockets is a lot of sockets for a client. That's like running a little server! But I can't really say without knowing more about what you're doing. I also write C++, not C#, though that may not be relevant here.

As far as "interference" on a single socket goes, the question is whether the server or your client is causing it. I'm guessing it should be possible to use a single socket. But to do so, you need to be able to forward an incoming event to the code that sent the request. Unless that event does something like echo an identifier that you sent with the request, forwarding it to the right place will be hard unless you know that a given event should always be routed to a specific requester and can hard-code this.

Greg Utas 2-May-22 14:14pm View

To have any hope of getting an answer, I think you'll have to provide more details about how often these logs are supposed to arrive, where they're stored, where the list of clients is maintained, on so on.

Greg Utas 1-May-22 11:21am View

True. But he posted a follow-up "code plz" question which revealed that this was for an exam that specifically requested him to demonstrate a unary operator being implemented as a friend. That question was subsequently closed for not being a proper question.

Greg Utas 1-May-22 7:52am View

Code needs to be there for a reason. If you removed the getch, you could also remove the #include conio.h. But then your program would exit immediately after performing its work, so you wouldn't be able to inspect what it had done. The getch is basically there as a debugging breakpoint. First time I've seen this. :)

Greg Utas 1-May-22 7:41am View

I was wondering what the getch at the end of your code was for and then realized it's probably just to stop the program from exiting until you enter something on the keyboard.

Greg Utas 1-May-22 7:34am View

Your code looks legal to me. I can't say whether it's complete, because that requires knowledge of what it's supposed to do. Unless you're specifically practicing the idea of implementing an operator overload outside a class, which can be useful for binary operators, I would just implement operator++ within the sample class. But its definition would then look different (no need for friend or the ob2 argument). It also needs to return a reference to the object. And there are two versions of operator++: prefix (which you have here) and postfix. Please read https://stackoverflow.com/questions/3846296/how-to-overload-the-operator-in-two-different-ways-for-postfix-a-and-prefix.

Greg Utas 1-May-22 7:26am View

Leaving out the & will result in a copy of the object being passed to the function. The work will be done on the copy, not the original object. To have the work done on the invoker's object, the object must be passed by reference. That is, the function receives a reference (secretly a pointer) to the object, which allows the work to be done on the external object rather than a copy.

Greg Utas 15-Apr-22 9:24am View

5, partly for being so kind. :)

Greg Utas 14-Apr-22 7:54am View

Gerry's suggestion is a good one. An alternative would be to draw a dashed line between the points where the signal was lost.

Greg Utas 14-Apr-22 7:50am View

I think the ladder would normally be displayed vertically, with asks above and bids below, with the number of bids or asks to the right of those numbers. The price of the last trade would be displayed separately. A histogram of volumes at each price is also useful but relies on historical data.

Greg Utas 28-Mar-22 7:41am View

I don't think you've posted the entire assignment. All the program has to do is input a bunch of data? Then what?!

Greg Utas 24-Mar-22 15:19pm View

You may find this helpful: https://www.cprogramming.com/reference/preprocessor/__FILE__.html.

Greg Utas 24-Mar-22 13:35pm View

You have to change the log system to add a filename (const char*) to each logging function, and then define a SetLogsForFile(const char* filename, bool onoff) function that front-ends a database that each logging function consults to see if the log should be suppressed.

That repository has a lot of code written by someone who knows how to code. If you just cloned it and want to play around with it, you should take on something easier first.

I am NOT writing the code.

Greg Utas 24-Mar-22 13:34pm View

Deleted

You have to change the log system to add a filename (const char*) to each logging function, and then a SetLogsForFile(const char* filename, bool onoff) function that front-ends a database.

That repository has a lot of code written by someone who knows how to write code. If you've just cloned it and want to play around with it, you should take on something easier first.

Greg Utas 24-Mar-22 12:39pm View

No. You didn't even tell me where myExample.cpp is located. I looked a bit but couldn't even find it! Stop wasting people's time.

Greg Utas 24-Mar-22 12:19pm View

There's a lot of code in there. I doubt anyone will sift through all of it and do this for you.

Greg Utas 24-Mar-22 7:10am View

You haven't told us what the errors are. You say there are no errors, but then you say that F5 finds 4. We don't even know what F5 does. Does it compile your program? Run it? If it only compiles it, then getting your program to compile is only the first step in getting it to work. A program of this size will probably contain execution errors, and you'll have to use a debugger to find those.

Greg Utas 22-Mar-22 8:05am View

What do you mean by "check the connection". It will certainly fail if the socket handle isn't valid, but that's about it. Because it only reads the keepalive option, it won't detect whether the socket is connected or whether a disconnect is pending.

Greg Utas 21-Mar-22 10:52am View

Then post what you've done and explain how it "breaks" your code. It could mean a compile error or a bug in running code. If it's the latter, you need to learn how to use a debugger, which is practically the only way to find and fix problems in non-trivial code.

Greg Utas 21-Mar-22 9:20am View

This is not your code, but the starting code that you've been given for your assignment. You haven't even added any code for the SAVE command, for loading the employee records from a file based on a command line parameter, or even stubs for the functions writeEmpToFile and readEmpFromFile. To put it bluntly, you're asking us to do all of your homework, and it's very unlikely that anyone will be willing to do that.

Greg Utas 18-Mar-22 9:00am View

Just writing name here is certainly more idiomatic and what you'd usually see.

Greg Utas 18-Mar-22 8:37am View

When you have more information about your original question, please just edit your question and add it there. This isn't a Solution and, even if it was, it's considered inappropriate to post a Solution to your own Question.

Greg Utas 17-Mar-22 12:57pm View

When you're running code this size and it doesn't work, it's time to learn how to use a debugger. You can't expect someone else to analyze or debug non-trivial code for you. A debugger lets you stop your code at whatever line you want and step through it a line at a time to see what's going on. It's the best way to find bugs in non-trivial code.

Greg Utas 17-Mar-22 9:57am View

You type faster than I do. :)

Greg Utas 17-Mar-22 9:12am View

5.

Greg Utas 16-Mar-22 20:08pm View

You're welcome.

Greg Utas 16-Mar-22 19:28pm View

LOL

Greg Utas 16-Mar-22 19:10pm View

But judging from the other answers, the & may not be needed, probably because str is an array and decays to a pointer. I've only written C++ and have never used scanf, so I'm unfamiliar with its vagaries.

Greg Utas 16-Mar-22 16:47pm View

5. Sadly, I don't think the debugging part will be needed after the & is added.

Greg Utas 16-Mar-22 16:28pm View

I know nothing about this topic but noticed you have several divisions by 64 in a nested for loop. If the compiler doesn't generate >> 6 for these, it would help to do that yourself.

Greg Utas 16-Mar-22 11:27am View

I do! You'd be amazed at some of the stupid mistakes I have to debug!

Greg Utas 16-Mar-22 11:27am View

Deleted

I do! You'd be amazed at some of the stupid mistakes I have to debug!

Greg Utas 16-Mar-22 8:47am View

Which probably means that there will be a follow-up question. :)

Greg Utas 15-Mar-22 18:16pm View

I wanted to leave the generation of the random number up to the poster, but you're quite right about the circular queue! I didn't read it carefully enough.

Greg Utas 10-Mar-22 16:11pm View

All this is Windows-specific. I use very little Windows stuff in my C++ code, and none of what you're using. You have to make sure that you've set up your Properties file to include the libraries that define these namespaces.

Greg Utas 10-Mar-22 9:42am View

I think that explains it, but you will probably have to show some code if you expect to get help.

Greg Utas 10-Mar-22 9:22am View

I can't even understand what the code is supposed to do. Regardless, you will probably have to show some actual code that you've written to try and solve the problem. It is unlikely that anyone here will write the code for you.

Greg Utas 7-Mar-22 12:16pm View

LOL

Greg Utas 7-Mar-22 8:42am View

5. I don't have your patience. :)

Greg Utas 26-Feb-22 14:57pm View

This is the kind of project that would be expected in a serious operating systems course. You can't possibly believe that anyone here is going to write this code and just give it to you.

Greg Utas 31-Jan-22 20:29pm View

Redefining a keyword is naughty. And many uses of #define are undesirable. It's fine in your own code, but not in code that others also use.

Greg Utas 31-Jan-22 11:32am View

You're welcome.

Greg Utas 31-Jan-22 10:51am View

It's not going to fix your problem, whatever it is, but exceptions should be caught by reference: catch(int& err). It won't matter for an int, but it can be important when the exception is an object.

Greg Utas 30-Jan-22 9:05am View

You can cast to whatever you want, but you risk blowing up if you
(a) use delete on a pointer that isn't the first vptr in the original object, or
(b) access a data member when there is another vptr in between.

Greg Utas 29-Jan-22 9:31am View

Thanks!

Greg Utas 29-Jan-22 6:43am View

Ah! Then you need to take out the #ifdef and #endif, and replace the #else with an else.

Greg Utas 23-Jan-22 8:08am View

Yes, I thought that was certainly possible.

Greg Utas 21-Jan-22 21:11pm View

I can't see the need for more than one socket unless you're communicating with different servers, when it might simplify things. Separating the socket (I/O) from the application is still a good idea because the I/O thread waits on the socket and the application thread waits for user actions like keyboard inputs or mouse events. When using more than one thread, watch out for critical sections! Part of the motivation for separating things is to keep each thread focused on a single job, without having to multiplex various responsibilities.

Greg Utas 21-Jan-22 8:25am View

It looks like you're trying to do GUI stuff on multiple platforms. I don't do GUI stuff, but I would try https://www.wxwidgets.org/ if I did. Open-source and free.

Greg Utas 21-Jan-22 7:57am View

I see that others have explained why constexpr can't be used for this purpose.

Greg Utas 7-Jan-22 15:56pm View

#if(0) is the same as #if 0, but I don't know what $if 0 is.

I think if(0) will compile what comes after the if, but you'll probably get a warning about unreachable code, and the compiler might be allowed to ignore that code.

What id 0 has to do with this, I don't know. It won't compile.

Greg Utas 4-Jan-22 12:29pm View

Doing this is a good idea. main should be kept fairly small. By moving pieces of it out into other functions, you break up the software into smaller, more understandable pieces that you might even be able to reuse. It also makes it easier to understand and evolve main itself.

Greg Utas 3-Jan-22 10:19am View

See std::unordered_multimap.

Greg Utas 3-Jan-22 7:42am View

Many containers that use hashing allow for collisions.

Greg Utas 28-Dec-21 6:47am View

5. Finding the MST sounds like a good way to start. See my above comment.

Greg Utas 28-Dec-21 6:45am View

See Solution 2, which may significantly help to optimize the code. If you find the minimal spanning tree and then do what I suggested, I think you'll find the same walk as if you applied my suggestion to the entire graph.

Greg Utas 26-Dec-21 18:43pm View

The algorithms that you mention deal with spanning trees, but it sounds like you want a path. Is that correct?

Greg Utas 26-Dec-21 9:14am View

I didn't look to see if a constant for pi was already defined in math.h.

Greg Utas 23-Dec-21 7:18am View

Thanks for pointing these out. Looks like I'll no longer be watching cat videos!

Greg Utas 21-Dec-21 13:58pm View

The time complexity of a sort algorithm is usually based on the number of comparisons.

Greg Utas 15-Dec-21 8:15am View

5, but you're spoiling him. :)

Greg Utas 11-Dec-21 7:27am View

If you've got the IP addresses and other details correct, see if the desktop has a firewall that is blocking incoming packets.

Greg Utas 26-Nov-21 18:48pm View

It appears to be a reference to one of his previous questions[^], where Richard contributed Solution 3.

Greg Utas 26-Nov-21 18:45pm View

It sounds like he wants an explanation of what the code does.

Greg Utas 24-Nov-21 7:27am View

Although the assignment didn't ask for it, the reason for defining a Date class, as suggested in Solution 2, is so that its constructor can check for illegal dates like April 31. Exactly what to do if such a date is specified depends on the program, but usually the constructor would use the throw operator to raise an exception.

Greg Utas 19-Nov-21 11:30am View

I don't know anything about binance and don't trade cryptos myself. I've only read about them and cannot answer your question in any more detail. As far as private keys are concerned, the exchange must carefully guard its own, or all of the tokens that it owns on behalf of users can get hacked. For the same reason, a user must guard their own private key. There is no way I would trust an exchange that did not give me my private key or allow me to transfer tokens to my own external wallet.

Greg Utas 19-Nov-21 8:08am View

Sorry that I couldn't resolve this. I don't have any more suggestions to offer.

Greg Utas 19-Nov-21 6:17am View

If this C++ program works, what's the purpose of writing it in Python?

This is probably your assignment. And unfortunately, this site rarely does people's assignments for them.

Greg Utas 19-Nov-21 6:06am View

A follow-up question. *Where* does the "undefined reference" error occur? My guess is that it occurs during linking, not compiling. But if there is additional information, such as a file and/or line number, please provide it.

Greg Utas 19-Nov-21 6:02am View

Yes, you could use extern, though I don't think it should be necessary. In test.h, you would use "extern" where you had used "static". In test.cpp, you'd use neither.

Greg Utas 16-Nov-21 6:32am View

You are talking about a specific type of system design. I was answering generally, because there are many other types of system designs. But even assuming that code uses the same design as your system, I can't think of an easier way to understand it.

Greg Utas 16-Nov-21 6:32am View

Deleted

You are talking about a specific type of system design. I was answering generally, because there are many other types of system designs. But even assuming that code uses the same design as your system, I can't think of an easier way to understand it.

Greg Utas 11-Nov-21 16:56pm View

"Page 2 of 6" means that anyone who provides code for what has been outlined thus far can expect a request for lots of enhancements.

Greg Utas 29-Oct-21 8:33am View

You haven't tried to do anything and have only asked to be given the answers. It is rare for anyone to respond to this type of request, and your post will probably get closed.

Greg Utas 27-Oct-21 9:36am View

Yes, but look at the code carefully. The first nested loop indexes arr[0-4][0-3] and the second one indexes arr[0-3][0-4]. One of them is wrong and will access memory that is outside the array.

Greg Utas 25-Oct-21 15:17pm View

I think you need to clarify a couple of things:
1. During serial execution, is snippet #1 supposed to finish before snippet #2 runs?
2. You talk about "each program" having 4 threads, but my guess is that you mean one program with 4 threads. Correct?

Greg Utas 22-Oct-21 9:04am View

I don't have a lot of experience with this, but he suggested a long long (probably 64 bits). That would reduce the number of collisions given that you're simply hashing on the contents of memory (effectively treating the input object as an array of bytes).

As far as the internals go, you might take bit 0 of the first byte, bit 1 of the second byte, bit 2 of the third byte, and so on. If the size of what you're hashing is less than 64 bytes, you could then wrap around and also take bit 1 of the first byte, bit 2 of the second byte, and so on until you have 64 bits.

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