C++
“C++ Primer” seem a bit aggressive?
So I only come from the slightest of coding background as I tried to learn python last year. Didn’t do too badly conceptually, but not having a job for it or really knowing what it could do, I fell out of interest. The reason I mention this is I have learned loops, if; else; elif, etc. Well recently I had an itch to learn c++ as it’s og but not too og. After some research I found many, Many people admiring “C++ primer”. I must say I am very disheartened for the rest of the book at chapter 1. In about 6 pages, it has discussed input/output, for loops, while loops, if/else.... without once explaining the nature of the function itself. Udemy courses and Python books I read spent whole chapters on loops, how they are iterated, best purposes for each type... I want to learn cpp because it gets much closer to the machine, which greatly excites me, but I’m worried the resource I’ve found in C++ Primer is not one that will truly teach me why I’m doing things. Am I completely wrong? submitted by /u/Rich_Foamy_Flan
[link] [comments]
“C++ Primer” seem a bit aggressive?
So I only come from the slightest of coding background as I tried to learn python last year. Didn’t do too badly conceptually, but not having a job for it or really knowing what it could do, I fell out of interest. The reason I mention this is I have learned loops, if; else; elif, etc. Well recently I had an itch to learn c++ as it’s og but not too og. After some research I found many, Many people admiring “C++ primer”. I must say I am very disheartened for the rest of the book at chapter 1. In about 6 pages, it has discussed input/output, for loops, while loops, if/else.... without once explaining the nature of the function itself. Udemy courses and Python books I read spent whole chapters on loops, how they are iterated, best purposes for each type... I want to learn cpp because it gets much closer to the machine, which greatly excites me, but I’m worried the resource I’ve found in C++ Primer is not one that will truly teach me why I’m doing things. Am I completely wrong? submitted by /u/Rich_Foamy_Flan
[link] [comments]
Fluent C++
Adapting STL Algorithms on Sets
This article is NWH, standing for Not Written Here. NWH is inspired from the NIH (Not Invented Here) syndrome which consists in refraining from using existing code from outside the company and reinventing the wheel every time. Just like it is good practice to look out for solutions developed elsewhere, we’re going to look at […]
The post Adapting STL Algorithms on Sets appeared first on Fluent C++.
Adapting STL Algorithms on Sets
This article is NWH, standing for Not Written Here. NWH is inspired from the NIH (Not Invented Here) syndrome which consists in refraining from using existing code from outside the company and reinventing the wheel every time. Just like it is good practice to look out for solutions developed elsewhere, we’re going to look at […]
The post Adapting STL Algorithms on Sets appeared first on Fluent C++.
C++
Join me for a ride! [Paid Oppertunity]
Hello Reddit, it's my girlfriends 1 year soon and I was thinking about different gift ideas. Until I came up with this brilliant idea that I think she would enjoy but it does require some knowledge that I would need help with. We are going to do long distances and I would like to create a website that displays a 24-hour timer and every time it hits 24 hours it displays a new message. I would also to get this done in c++ because that is the language I am learning. I know I currently would not be able to do this at all and would need someone to help me out. I am willing to pay if someone could help me with this project whilst explaining to me whats going on. If you think you could do this please let me know and shoot me a message. Thank you in advance and have a good day. submitted by /u/MrMinimize
[link] [comments]
Join me for a ride! [Paid Oppertunity]
Hello Reddit, it's my girlfriends 1 year soon and I was thinking about different gift ideas. Until I came up with this brilliant idea that I think she would enjoy but it does require some knowledge that I would need help with. We are going to do long distances and I would like to create a website that displays a 24-hour timer and every time it hits 24 hours it displays a new message. I would also to get this done in c++ because that is the language I am learning. I know I currently would not be able to do this at all and would need someone to help me out. I am willing to pay if someone could help me with this project whilst explaining to me whats going on. If you think you could do this please let me know and shoot me a message. Thank you in advance and have a good day. submitted by /u/MrMinimize
[link] [comments]
CppCon (Youtube)
How C++20 Changes the Way We Write Code - Timur Doumler - CppCon 2020
https://cppcon.org/
https://github.com/CppCon/CppCon2020
---
The upcoming C++20 standard is the biggest update in a decade. Its feature set and their impact on how we write C++ will be as large, and possibly larger than that of C++11.
In this talk we will look at how new features like concepts, coroutines, and modules will fundamentally change the way we design libraries, the way we think about functions, and even the way we compile our code. We will also mention some long-standing warts in C++ which are finally cured.
---
Timur Doumler is a C++ developer specialising in audio and music technology, an active member of the ISO C++ committee, and Conference Chair of the Audio Developer Conference (ADC). He is passionate about building communities, clean code, good tools, and the evoluti...
Read full post
How C++20 Changes the Way We Write Code - Timur Doumler - CppCon 2020
https://cppcon.org/
https://github.com/CppCon/CppCon2020
---
The upcoming C++20 standard is the biggest update in a decade. Its feature set and their impact on how we write C++ will be as large, and possibly larger than that of C++11.
In this talk we will look at how new features like concepts, coroutines, and modules will fundamentally change the way we design libraries, the way we think about functions, and even the way we compile our code. We will also mention some long-standing warts in C++ which are finally cured.
---
Timur Doumler is a C++ developer specialising in audio and music technology, an active member of the ISO C++ committee, and Conference Chair of the Audio Developer Conference (ADC). He is passionate about building communities, clean code, good tools, and the evoluti...
Read full post
Arthur O’Dwyer
Inheritance is for sharing an interface (and so is overloading)
This blog post was inspired by my answer to a question
on Code Review StackExchange. To utterly oversimplify the question: When is it appropriate
to use classical inheritance?
Here’s what the same code would look like, with an
(and omitting the NVI
for pedagogical reasons):
The only reason to use a base class here is in order to write polymorphic code that operates
on (a pointer or reference to) that base class.
If you don’t need to write
Abstraction is a tool for solving problems — and, as such, it is also a signal to the reader
that a problem is being solved! If your code doesn’t actually need polymorphism in order
to work, then you should avoid making an inheritance hierarchy.
Keep it simple, stupid.
The design principles of polymorphic programming apply equally to generic programming…
When should I name two methods the same?
Notice that in our original
and
However, this is once again a signal to the reader that something indispensable is
going on here! Meowing and barking are vaguely similar at an abstract level, yes;
but abstraction is a tool for solving problems, and so we should avoid it unless
a problem exists to be solved.
The only reason to use the same name for meowing and barking, here, is in order
to write generic code that operates on an object of unknown type
Notice that another way to ask “When should I name two methods the same?”
is to ask “When should I define a C++20
The rules of classical OOP are isomorphic to the rules of generic programming with
concepts: just replace “base class” with “concept” and “derives from” with “models.”
Let’s go deeper.
When should I put two functions into an overload set?
The previous section was about reusing the same name outside of an overload set:
this?
Should we rename both methods to just
The only reason to use the sa
Inheritance is for sharing an interface (and so is overloading)
This blog post was inspired by my answer to a question
on Code Review StackExchange. To utterly oversimplify the question: When is it appropriate
to use classical inheritance?
struct Cat {
void meow();
};
struct Dog {
void bark();
};
// Should I write a struct AbstractAnimal?
Here’s what the same code would look like, with an
AbstractAnimal base class(and omitting the NVI
for pedagogical reasons):
struct AbstractAnimal {
virtual void do_speak() = 0;
};
struct Cat : public AbstractAnimal {
void meow();
private:
void do_speak() override { meow(); }
};
struct Dog : public AbstractAnimal {
void bark();
private:
void do_speak() override { bark(); }
};
The only reason to use a base class here is in order to write polymorphic code that operates
on (a pointer or reference to) that base class.
// If all my code looks like this, I don't need a base class.
void operateOnCat(Cat *c) { c->meow(); }
operateOnCat(myCat);
// I need the base class only if I want to write code like this.
void operateOnAnything(AbstractAnimal *a) { a->do_speak(); }
operateOnAnything(myCat);
operateOnAnything(myDog);
If you don’t need to write
operateOnAnything, then you shouldn’t write AbstractAnimal.Abstraction is a tool for solving problems — and, as such, it is also a signal to the reader
that a problem is being solved! If your code doesn’t actually need polymorphism in order
to work, then you should avoid making an inheritance hierarchy.
Keep it simple, stupid.
The design principles of polymorphic programming apply equally to generic programming…
When should I name two methods the same?
Notice that in our original
Cat/Dog code, I named the two methods Cat::meow()and
Dog::bark(). It’s very tempting to give them the same name:struct Cat {
void talk(); // meows
};
struct Dog {
void talk(); // barks
};
However, this is once again a signal to the reader that something indispensable is
going on here! Meowing and barking are vaguely similar at an abstract level, yes;
but abstraction is a tool for solving problems, and so we should avoid it unless
a problem exists to be solved.
The only reason to use the same name for meowing and barking, here, is in order
to write generic code that operates on an object of unknown type
T.// If all my code looks like this, I don't need to reuse the
// same name in both classes.
void operateOnCat(Cat& c) { c.meow(); }
operateOnCat(myCat);
// I need the same name only if I want to write code like this.
template
void operateOnAnything(T& t) { t.talk(); }
operateOnAnything(myCat);
operateOnAnything(myDog);
Notice that another way to ask “When should I name two methods the same?”
is to ask “When should I define a C++20
concept modeled by both these classes?”The rules of classical OOP are isomorphic to the rules of generic programming with
concepts: just replace “base class” with “concept” and “derives from” with “models.”
Let’s go deeper.
When should I put two functions into an overload set?
The previous section was about reusing the same name outside of an overload set:
Cat::talk and Dog::talk aren’t “overloads” per se. But what about something likethis?
struct Snake {
void eatPellet(const Pellet&);
void eatCat(const Cat&);
};
Should we rename both methods to just
Snake::eat, creating an overload set?The only reason to use the sa
C++
periodic_function v0.1.0 released! Thank you all for the helpful feedback!
A while back I made my initial post about the
[link] [comments]
periodic_function v0.1.0 released! Thank you all for the helpful feedback!
A while back I made my initial post about the
periodic_function library I had created and I receive a ton of feedback. Thank you so much to everyone who commented. Your suggestions and critical eyes have made the library more robust and better overall. The suggestions and comments have been addressed in the v0.1.0 release and I hope some of you can find it useful. Thank you again! I really appreciate those who took the time to nitpick my code; it was eye-opening and a great learning experience. Release is here. submitted by /u/mrkent27 [link] [comments]
C++
Introducing fp library
Hi, the author of Dragonbox again. I'm now working on a more comprehensive library with features related to conversions between strings and floating-point numbers. It's in an early stage and is not really usable right now AFAICT, but I want to gather some opinions from you guys. Please take a look at the repo if you are interested. Any idea/feedback is very welcome, and contribution is even more welcome. As stated in the README, the goal of the library is to provide conversion algorithms between decimal and binary floating-point numbers rather than string parsing/formatting. String parsing/formatting routines provided in the library should be considered as proof-of-concepts, although I'll continue to work on improving them as well. Therefore, I put much effort on cleanly separate decimal/binary conversion routines from string parsing/formatting as much as possible. Currently, the library has the following features (with rudimentary/subject-to-change API's): Dragonbox: shortest-roundtrip binary-to-decimal conversion algorithm for formatting. The version in this library is not really different from the original implementation, except that it uses a larger table (in order to share it with the parsing algorithm). Ryu-printf: fixed-precision binary-to-decimal conversion algorithm for formatting. This is nothing more than just an implementation of the algorithm as written in the paper with a few modifications, but somewhat mysteriously it uses way fewer amount of static data compared to the original implementation by Ulf Adams. (I honestly have no idea why this happened.) But the size of static data is still huge; it's about 40KB. Dooly: limited-precision (9 for
[link] [comments]
Introducing fp library
Hi, the author of Dragonbox again. I'm now working on a more comprehensive library with features related to conversions between strings and floating-point numbers. It's in an early stage and is not really usable right now AFAICT, but I want to gather some opinions from you guys. Please take a look at the repo if you are interested. Any idea/feedback is very welcome, and contribution is even more welcome. As stated in the README, the goal of the library is to provide conversion algorithms between decimal and binary floating-point numbers rather than string parsing/formatting. String parsing/formatting routines provided in the library should be considered as proof-of-concepts, although I'll continue to work on improving them as well. Therefore, I put much effort on cleanly separate decimal/binary conversion routines from string parsing/formatting as much as possible. Currently, the library has the following features (with rudimentary/subject-to-change API's): Dragonbox: shortest-roundtrip binary-to-decimal conversion algorithm for formatting. The version in this library is not really different from the original implementation, except that it uses a larger table (in order to share it with the parsing algorithm). Ryu-printf: fixed-precision binary-to-decimal conversion algorithm for formatting. This is nothing more than just an implementation of the algorithm as written in the paper with a few modifications, but somewhat mysteriously it uses way fewer amount of static data compared to the original implementation by Ulf Adams. (I honestly have no idea why this happened.) But the size of static data is still huge; it's about 40KB. Dooly: limited-precision (9 for
float's, 17 for double's) decimal-to-binary conversion algorithm for parsing. This is the one that I mentioned in the previous post about Dragonbox. Ryu library also provides a similar algorithm, and it seems that the performances of these algorithms are similar. Combining Dooly and (a slight extension of) Ryu-printf, string-to-float parsing for arbitrary length input is also possible. A gist of the idea is explained in the comment of /u/STL in this post. (I originally got the idea from discussions with fast_io's author, though.) /u/STL said that it might be agonizingly slow, but it turned out to be a lot faster than the current implementation of MS STL's std::from_chars. (To be fair, my implementation does way fewer error handlings so the actual performance gap should be somewhat smaller.) submitted by /u/jk-jeon [link] [comments]
CppCon (Youtube)
Empirically Measuring, & Reducing, C++’s Accidental Complexity - Herb Sutter - CppCon 2020
https://cppcon.org/
https://github.com/CppCon/CppCon2020
---
We often hear “C++ is more complex than it needs to be,” typically demonstrated using anecdotes and “gotcha” examples. Those can be valid and demonstrate real pain points, but it would be nice to have more quantifiable data that we could analyze to measure sources of complexity. This talk reports work to systematically catalog and measure C++’s unneeded complexity, how some current evolution proposals may address its major sources, and presents specific suggestions on what we might be able to do about it in the context of a future-evolution proposal to simplify parameter passing and provide meaningful initialization guarantees in C++.
---
Herb is the chair of the ISO C++ standards committee, a programming...
Read full post
Empirically Measuring, & Reducing, C++’s Accidental Complexity - Herb Sutter - CppCon 2020
https://cppcon.org/
https://github.com/CppCon/CppCon2020
---
We often hear “C++ is more complex than it needs to be,” typically demonstrated using anecdotes and “gotcha” examples. Those can be valid and demonstrate real pain points, but it would be nice to have more quantifiable data that we could analyze to measure sources of complexity. This talk reports work to systematically catalog and measure C++’s unneeded complexity, how some current evolution proposals may address its major sources, and presents specific suggestions on what we might be able to do about it in the context of a future-evolution proposal to simplify parameter passing and provide meaningful initialization guarantees in C++.
---
Herb is the chair of the ISO C++ standards committee, a programming...
Read full post
C++
Potential way to solve dangling reference to temporary?
When I am writing when() in SugarPP, I kept wondering how to deal with returning reference of possibly lvalue references and rvalue reference. To make it simpler, it's the same as
[link] [comments]
Potential way to solve dangling reference to temporary?
When I am writing when() in SugarPP, I kept wondering how to deal with returning reference of possibly lvalue references and rvalue reference. To make it simpler, it's the same as
cpp int x{}; auto&& bigger = std::max(x, -1); //... Use bigger, OK, but dangling if -1 is bigger I gave up by just return by value. But it's obviously not optimal if I also want to be able to modify through the reference (both the lvalue or the temporary), as if the temporary is also lvalue. Of course I can just give it a name to trivially solve it but still it's amazingly unintuitive. What if the compiler can implicitly generate a name to make the temporary to a lvalue when the function accepts reference (because temporary will still "materialize" anyway) at the current calling scope, but still interpret it as rvalues like this: cpp int x{}; int __temp = -1; auto&& bigger = std::max(x, std::move(__temp)); //... Use bigger, OK now submitted by /u/HO-COOH [link] [comments]
C++ – Типизированный язык программирования
Тестирование приложений в условиях нехватки памяти
Вопрос о том надо ли проверять то, что возвращает
Часть людей считает, что надо пытаться обрабатывать все виды runtime ошибок, в т.ч. и OOM ситуации. Другие считают, что с OOM всё равно мало что можно сделать и лучше дать приложению просто упасть. На стороне второй группы людей ещё и тот факт, что дополнительная логика обработки OOM с трудом поддаётся тестированию. А если код не тестируется, то почти наверняка он не работает.
Я полностью согласен с тем, что не стоит реализовывать логику обработки ошибок которую вы не собираетесь тестировать. Почти наверняка она ничего не улучшит, а может и того хуже — всё испортит.
Вопрос о том надо ли пытаться обрабатывать OOM ситуации в библиотеках/приложениях является противоречивым и мы не будем его здесь касаться. В рамках данной публикации я лишь хочу поделиться опытом того как можно тестировать реализованную логику обработки OOM ситуаций в приложениях написанных на C/C++. Разговор будет идти об операционных системах Linux и macOS. Ввиду ряда причин, Windows будет обойдён стороной. Читать дальше →
Тестирование приложений в условиях нехватки памяти
Вопрос о том надо ли проверять то, что возвращает
malloc является спорным и всегда порождает жаркие дискуссии.Часть людей считает, что надо пытаться обрабатывать все виды runtime ошибок, в т.ч. и OOM ситуации. Другие считают, что с OOM всё равно мало что можно сделать и лучше дать приложению просто упасть. На стороне второй группы людей ещё и тот факт, что дополнительная логика обработки OOM с трудом поддаётся тестированию. А если код не тестируется, то почти наверняка он не работает.
Я полностью согласен с тем, что не стоит реализовывать логику обработки ошибок которую вы не собираетесь тестировать. Почти наверняка она ничего не улучшит, а может и того хуже — всё испортит.
Вопрос о том надо ли пытаться обрабатывать OOM ситуации в библиотеках/приложениях является противоречивым и мы не будем его здесь касаться. В рамках данной публикации я лишь хочу поделиться опытом того как можно тестировать реализованную логику обработки OOM ситуаций в приложениях написанных на C/C++. Разговор будет идти об операционных системах Linux и macOS. Ввиду ряда причин, Windows будет обойдён стороной. Читать дальше →