@programminginc - страница 2459

Anonymous

lol

Lele fer lola

数学の恋人

You think that's funny?

Anonymous

No

数学の恋人

then stop doing that

Anonymous

Okay sorry. I thought u are chinese. Again sorry.

数学の恋人

Okay sorry. I thought u are chinese. Again sorry.

Still bruh

Pavel

What is a good way to remove elements from a vector in positions given in another vector (std::vector<size_t> indexesToRemove)?

数学の恋人

What is a good way to remove elements from a vector in positions given in another vector (std::vector<size_t> indexesToRemove)?

naive approach I can think just now is, iterate through the index vector and remove with std::vector::erase

Pavel

naive approach I can think just now is, iterate through the index vector and remove with std::vector::erase

Yep, but it's probably not very efficient because we will move elemens on the right in each iteration.

Pavel

Maybe iterating in reverse and erase should be better 🤔

数学の恋人

what about iterating over the original vector and use std::find to find the current index in indexesToRemove vector?

数学の恋人

what about iterating over the original vector and use std::find to find the current index in indexesToRemove vector?

this seems like overkill though, not even efficient than previous one

数学の恋人

Yep, but it's probably not very efficient because we will move elemens on the right in each iteration.

I don't think that will make any difference

Anonymous

actually I'm using constructors of different types and let compiler decide the type. see image.

Why you use const& for primitive types?

Pavel

Hm, indexesToRemove is rather big, so the original vector, but it may worth it to convert it to unordered_map for example. Not sure, probably need to get more sleep :)

数学の恋人

Why you use const& for primitive types?

references

Anonymous

references

Why???

数学の恋人

Why???

is it bad?

Anonymous

is it bad?

Yes

Pavel

I don't think that will make any difference

Well, in case of reverse iterating we will move less elements (won't move elements that going to be removed anyway), but yes, that's a minor win

数学の恋人

Yes

I don't think that makes any difference there, pass by value or pass by reference does it really matter that much?

数学の恋人

Well, in case of reverse iterating we will move less elements (won't move elements that going to be removed anyway), but yes, that's a minor win

so the vector is sorted, am I right?

Cengizhan

Yes

Why?

Pavel

so the vector is sorted, am I right?

Ah, well, no, I thought it sorted but now when you asked I understood that it's not.

数学の恋人

Ah, well, no, I thought it sorted but now when you asked I understood that it's not.

Hmm... then it shouldn't really make difference

Pavel

Yes. OK, I guess I will go with just iterate and erase and will think about it later. Thanks :)

数学の恋人

Please do tell us if you find anything efficient.

Pavel

Please do tell us if you find anything efficient.

Sure

Pavel

No, but I can sort it :)

数学の恋人

what about iterating over the original vector and use std::find to find the current index in indexesToRemove vector?

this approach doesn't seem that bad also

Pavel

Why?

Types like int can be passed using registers or stack. That's more efficient than passing a reference to it. And there's another issue (I forgot how it called): The compiler can be forced to generate code that reads variable from memory more often in case it can't be sure the variable you passed isn't changed inside your function. Here is an example of such problem in a bad case. https://en.m.wikipedia.org/wiki/Load-Hit-Store

数学の恋人

basically extra space

Pavel

That sounds like a very good solution (can't think if it could be done more efficient than this one), thanks

数学の恋人

oh right just reread the whole thing

数学の恋人

Yes

Thanks for the suggestion I corrected/recfactored it

Cengizhan

Types like int can be passed using registers or stack. That's more efficient than passing a reference to it. And there's another issue (I forgot how it called): The compiler can be forced to generate code that reads variable from memory more often in case it can't be sure the variable you passed isn't changed inside your function. Here is an example of such problem in a bad case. https://en.m.wikipedia.org/wiki/Load-Hit-Store

Yeah I know that but this seems pretty time-critical application requirement and until that level, many optimization can be done.

Anonymous

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-in @maths_lover @cngzhnp

数学の恋人

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-in @maths_lover @cngzhnp

Thank you will look later

数学の恋人

gone in my saved messages

Cengizhan

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-in @maths_lover @cngzhnp

Thanks , TIL.

数学の恋人

is this okay to do? int someFunc(const int, int*) { } // Then calling like int num = 0; num = someFunc(num, &somePointerAddr);

Alex

yes

数学の恋人

or should I do like, int num; const int tempNum = 0; num = someFunc(num, &someAddr);

Alex

or should I do like, int num; const int tempNum = 0; num = someFunc(num, &someAddr);

I can`t see any reason to do like this

Alex

first option is ok

数学の恋人

ok thanks

Wisenky

Guys , I want to build an rpg multiplayer cross-platform game with using cpp , I look at sdl sfml and unreal engine . Should I learn using a software like sdl for building it or an engine . Im so confused , would you lead me guys ?

Asdew

Do you want to make an engine and a game or just a game?

Wisenky

Do you want to make an engine and a game or just a game?

Just a game

Asdew

Then you want to use a game engine.

Wisenky

Then you want to use a game engine.

Is it a must thing using engine for making a game ?

klimi

Is it a must thing using engine for making a game ?

If you're not crazy, yes

Wisenky

Oh sad :(

klimi

I mean you could make your own game engine but... You would still use one

Asdew

Well, if you don't use a game engine that was not made specifically for your game, then you'll develop it along the way.

klimi

Exactly

Wisenky

Well, if you don't use a game engine that was not made specifically for your game, then you'll develop it along the way.

And its so hard ?

Asdew

Well, not really hard.

Wisenky

Do you mean that I should use an engine that made before

Wisenky

Or making a new one specifically for mine

数学の恋人

Or making a new one specifically for mine

I guess first you can try making your game with an engine and learn how engine works in gneral then you might as well make one engine yourselves

Wisenky

I guess first you can try making your game with an engine and learn how engine works in gneral then you might as well make one engine yourselves

Which one should I choose

数学の恋人

Which one should I choose

any should be fine, though I think you can go for unreal

Wisenky

Thanks for your opinions guys

Asdew

Godot is better.

Dima

UE:)

Tokin

Thanks for your opinions guys

Just make an engine dude.. Might take years if you are asking the questions... But fun process.. You'll learn a lot..

Anonymous

Hi guys this may be off topic but then I would appreciate. Does anyone know of a framework or api I can embed in a c# desktop app to track its analystics the way playstore tracks our Android apps.

Anonymous

Is it a must thing using engine for making a game ?

https://www.youtube.com/c/TheChernoProject If you're interested in making game engine, watch the channel

数学の恋人

Lol banned quietly

@unchanted

gets, getchar, puts, putchar, getch, putch... When, where and how to use them what is the difference in all these? Which compiler understand which keyword...

Anonymous

gets, getchar, puts, putchar, getch, putch... When, where and how to use them what is the difference in all these? Which compiler understand which keyword...

Read the docs

@unchanted

Read the docs

Can you share me the document?

Anonymous

Can you share me the document?

cppreference.com

@unchanted

gets, getchar, puts, putchar, getch, putch... When, where and how to use them what is the difference in all these? Which compiler understand which keyword...

And which compiler understand which keyword?