std::string_view can optimize both performance and code readability in code sections which handle strings, but, it can also lead to UB and memory issues if used incorrectly.

Maintain Your Iterations – Iterators Customization – Part 3

by Coral Kashri

Iterators Customization

C++ Helps Your Compiler to Help You

by Coral Kashri

How compiler helps code run faster and generates warnings in single cross-compiler way

All Articles

top

C++20

An Introduction to C++ Concepts for Template Specialization

8 Sep 2022 by Bruno van Dooren

How concepts can be used in template programming for partial specialization

C++20

C++

templates

Retro Game Cartography: Part Deux

9 Sep 2021 by Mladen Janković

Improved algorithm for reconstructing game world map from captured game play

Using the Win32 Cryptographic API to Hash Data

26 Aug 2022 by Bruno van Dooren

This article describes a way to hash data using the latest Win32 API and C++

C++ GroupBy

17 Mar 2023 by Claudio Farassino

A small and simple C++ GroupBy with the same syntax and use of DotNet GroupBy

C++20

C++

qTimeLineEditor - A flexible graphical time line editor for your animations

19 Sep 2020 by sdancer75

A graphical time line editor to help you create and prototype animations. It is useful for adjusting variables and checking out how the effects change over time with keyframing and easing/twining functions.

How to define method specialization of templated class outside of class declaration

15 Dec 2021 by Greg Utas

You can't specialize the function template without also specializing the class template to which it belongs. See here[^].

C++20

[Solved] static and non-static init block in C++

31 Dec 2021 by Richard MacCutchan

You could probably simplify that by the use of the singleton pattern - Google Search[^].

[Solved] static and non-static init block in C++

5 Jan 2022 by Stefan_Lang

You seem to try and imprint another languages' properties onto C++, and that is never a good idea! My experience with java is limited, and I'm not sure what you actually have in mind, but the code you posted is clearly not the recommended way of...

[Solved] why I cannot properly overload an operator with a templated param?

14 Jan 2022 by steveb

std::cout

C++20, module declaration & definition unit for templated logic

25 Jan 2022 by Stefan_Lang

Quote: How do we do it right 1. Post your actual question at the top, maybe even in the topic heading 2. Provide your goal and relevant detail information after that, in the body of your posting. Make sure to keep it reasonably short by...

Enforcing a Static Interface in C++

2 Feb 2023 by Bruno van Dooren

Ways to enforce an interface contract on static methods, similar to what you would expect from static virtual methods if they'd exist in C++

Power Range(r)s – C++20

22 Apr 2023 by Coral Kashri

About C++20 Ranges library

C++20

C++

How do I get this code to work

17 Sep 2023 by Michael Haephrati

The best solution I found is but it seems to be a flaw in std::format. #include #include #include #include #include #include #include #include std::string...

C++20

How do I pass an identifier to a macro?

15 Jul 2021 by OriginalGriff

Spelling is all ... change: #define HANDLE_NULL_BUFFER(buffer_identifer) DEBUG_ASSERT(buffer_identifier != nullptr) To #define HANDLE_NULL_BUFFER(buffer_identifier) DEBUG_ASSERT(buffer_identifier != nullptr) ...

C++20

C++20, module declaration & definition unit for templated logic

27 Jan 2022 by Stefan_Lang

Quote: The problem was I cannot properly separate the declaration & definition of a templated symbols such as classes, structs, functions, and many more Short answer: you cannot! From the link I posted above (emphasis mine): Quote: However, when...

Unable to get user input in the day 1 problem of advent of code 2022

5 Dec 2022 by OriginalGriff

Quote: The below code is what I have tried but it's entirely wrong! Yes. It is. And you don't know why. Fortunately, you have a tool available to you which will help you find out what is going on: the debugger. How you use it depends on your...

C++20 template specialization

24 Dec 2022 by honey the codewitch

Your code initially looked fine to me and then I saw it. You can't specialize by number of template arguments in C++ because you must have parameters after struct xyz, such as struct xyz as specializations require some of the template...

C++20

Queue-like Data Structure for Hierarchy-based Scheduling

25 Nov 2020 by Mladen Janković

Data structure that allows items to be scheduled for processing based on the tags that define item hierarchy

The answer to the equation

28 Apr 2021 by Rick York

This is not a code conversion service but I will give you a hint. The Pascal for loop of this form : for x1 :=0 to 12 do looks like this in c++ : for( x1 = 0; x1

Why is the copy constructor not called

16 Dec 2021 by BernardIE5317

In the code below why is the templated foobar called and not the non-templated version I expect the non-templated version to be called as it is a precise argument match w/ the exception of the const void foobar(const int&) { } // not called...

C++20

[Solved] static and non-static init block in C++

5 Jan 2022 by Phoenix Liveon

What I did for now was to call/invoked it inside of the first line of one of any constructor, Note: upon by doing it we need to have a delegated constructor if we do had multiple overloaded constructors, so that we could link it together, then...

Pepper

4 Aug 2022 by Jovibor

PE (x86) and PE+ (x64) files viewer, based on libpe.

C++20

editor

GUI

How do I use formatting escape character in std::format

17 Aug 2022 by 2022 Dude

in C++ 20, there is a new method for formatting strings, called std::format. However, its hot clear how (and would it be possible) to format the output, especially float values where you would want to control how many digits after the decimal...

C++20

How do I use formatting escape character in std::format

15 Aug 2022 by Greg Utas

I've only skimmed this article, but you might find it helpful: An Extraterrestrial Guide to C++20 Text Formatting - C++ Stories[^] If there's already a standard way to do it, that's what I'd use. So far, I've found little use for all the things...

C++20

How do I use formatting escape character in std::format

15 Aug 2022 by Richard MacCutchan

See std::formatter - cppreference.com[^] which explains all the fields is a format selector.

C++20

How to convert system command output to string ?

16 Oct 2022 by merano99

The command system() creates a new process to handle the specified command. char cmd[10]; strcpy(cmd, "dir"); system(cmd); In most cases, this is neither performant nor useful. But of course you can start a process with C this way. You could...

How to convert system command output to string ?

19 Oct 2022 by Alexandrnn

#include #include int main() { system("dir"); puts((char*)stdin); } #include #include #include int main() { char cmd[10]; strcpy_s(cmd, 10, "dir"); system(cmd); puts((char*)stdin); }

How to delete a key from the registry using C++ ?

20 Oct 2022 by Rick York

Have you investigated the RegDeleteKeyExA function (winreg.h) - Win32 apps | Microsoft Learn[^] ? Here is another sample : Deleting Registry Key with Subkeys Win32 C program example[^]

Unable to get user input in the day 1 problem of advent of code 2022

5 Dec 2022 by merano99

Saving the calories in a vector would be a good idea. std::vector numbers; Then it would be practical to write the calories as described in a file calories.txt and read this file line by line. At each blank line write the sum into the...

C++20 template specialization

24 Dec 2022 by CPallini

Try template struct xyz { static size_t const data = 1; }; template struct xyz { static size_t const data = 0; }; template struct xyz { static size_t const data = 0; }; auto x1 =...

C++20

How to utilize "format" in C++?

9 Jun 2022 by BernardIE5317

Greetings Kind Regards I am completely befuddled re/ C++ format. The code below generates the compiler errors shown. Kindly Advise Thank You #include #include void foo(std::string_view _format) { std::cout

C++20

C++20 constrained auto&& not a "universal reference"

18 Jan 2024 by Richard MacCutchan

Maybe this: Constraints and concepts (since C++20) - cppreference.com[^].

C++20

Why this udp socket not work when I run it in pc outside the network ?

26 Sep 2022 by Death Smoke

I'm trying to make a connection between two computers both of them are using tp-link adapter , but i'm not receving anything from client . #include #include using namespace std; int main() { ...

How do I write the algorithm of the question said to write a C++ program to read five integer elements into an array and find their sum "

3 May 2021 by OriginalGriff

Your code compiles, runs and produces a correct answer: so what more is necessary? If what you have isn't enough, you need to go back to your exact assignment, read it again very carefully, and work out what exactly it expects you to hand in. ...

C++20

Getting todolist to work on new windows PC

3 Jul 2021 by OriginalGriff

Don't post this under Quick Answers - if you got the code from an article, then there is a "Add a Comment or Question" button at the bottom of that article, which causes an email to be sent to the author. They are then alerted that you wish to...

C++20

Why is the base class public method not found?

4 Jul 2021 by BernardIE5317

Why is cbase::foobar() not found when called on type cderived while all members of cbase are declared public? This suggests name only is utilized for lookup and signature ignored but that is difficult to believe as one of the benefits of C++ is...

C++20

Getting todolist to work on new windows PC

3 Jul 2021 by Richard MacCutchan

See ToDoList 8.0 - An Effective and Flexible Way to Keep on Top of Your Tasks[^]. There is a forum at the end of the article where you can post a message to the author.

C++20

Why is the base class public method not found?

4 Jul 2021 by Richard MacCutchan

Variable d is an instantiation of a cderived class. So any call to foobar requires an integer to be passed to it, as per the signature of the function in that class. In order to call the base version you need to cast d to a cbase object thus: ...

C++20

How to write a concept which requires a class type have a particular templated method?

5 Jul 2021 by BernardIE5317

Is it possible to write a concept which requires a class type have a particular templated method as below? struct struct_a { template void foobar(T&) {} } template requires templated_foobar // how to write this...

C++20

How to write a concept which requires a class type have a particular templated method?

5 Jul 2021 by Richard MacCutchan

See Templates - cppreference.com[^]

C++20

How to write a concept which requires a class type have a particular templated method?

5 Jul 2021 by Greg Utas

The page mentioned above links to this[^], which covers the details. Sorry I can't help beyond that, because I don't use constraints.

C++20

How do I pass an identifier to a macro?

15 Jul 2021 by BernardIE5317

The C++ code below will not compile w/ error C2065: 'buffer_identifier': undeclared identifier I do not understand why the argument passed to DEBUG_ASSERT from HANDLE_NULL_BUFFER is not replaced by the argument passed to HANDLE_NULL_BUFFER ...

C++20

User-defined literal doesn't work when the definition is written in a different .cpp file

27 Aug 2021 by Khiêm Nguyễn 2021

I created a user-defined literal like this in is OWN .cpp file (declared as a friend function in .h file): fraction operator"" _frac(const long double val) { return fraction(static_cast(val)); } But in main it...

C++20

C++

debugging

User-defined literal doesn't work when the definition is written in a different .cpp file

27 Aug 2021 by Rick York

Do you have a prototype for the function defined? Something like : extern fraction operator _frac(const long double val);

C++20

C++

debugging

How do I simulate the interaction of two point masses(gravitational pull) using the verlet algorithm?

21 Nov 2021 by CrystalNeves

Hello. I am trying to implement verlet's algorithm to simulate the interaction of two stars with the same mass as the sun. They are initially 2 parsec away and symetric velocities perpendicular to the axis that passes through their centre. ...

C++20

How to resolve link error

10 Dec 2021 by BernardIE5317

The code below does not link as indicated Kindly advise Thank You struct cfoobar { struct cgoobar { void goobar() const {} }; static cgoobar m_goobar; // error LNK2001: unresolved external symbol "public: static struct cfoobar::cgoobar...

C++20

How to resolve link error

10 Dec 2021 by k5054

As for basic type, you have to initialize the static variable before you can use it struct cfoobar { struct cgoobar { void goobar() const {} } static cgoobar m_goobar; }; cfoobar::cgoobar::m_goobar; //initializes...

C++20

How to resolve link error

10 Dec 2021 by BernardIE5317

#define FUNCSIG cout

C++20

How to define method specialization of templated class outside of class declaration

15 Dec 2021 by BernardIE5317

I wish to define a specialization of a templated class's templated method outside of the class declaration as shown below However the indicated error message is generated No error occurs if the class is not templated Thank You Kindly ...

C++20

[Solved] static and non-static init block in C++

22 May 2022 by Phoenix Liveon

��Is there a way to have this initialization block similar to Java that we could implement and run properly in C++. There were two types of init-block in Java: 1. init-block/raw-init-block, this will invoke at every new instance created. 2....

How to utilize "format" in C++?

9 Jun 2022 by Member 14138220

The problem seems to be consteval _Basic_format_string constructor that cannot convert runtime strings like that. std::_Basic_format_string s = _format; I went with using the underlying vformat() method that doesn't enforce this...

C++20

How to resolve C++ compiler error re / std::optional<...> can not deduce template types

31 Aug 2022 by BernardIE5317

Greetings Kind Regards I am attempting to call a C++ routine which accepts a std::optional argument. However when called w / an argument whose type is the contained type it fails to compile stating the template types could not be deduced....

C++20

How to resolve C++ compiler error re / std::optional<...> can not deduce template types

31 Aug 2022 by Greg Utas

The following compiles for me in C++20 (MSVC). I had to add a few missing semicolons and comment out most of the calls to the SHOW macro, which generated errors for too many arguments. I also added spaces around template arguments to prevent left...

C++20

How to resolve C++ compiler error re / std::optional<...> can not deduce template types

31 Aug 2022 by BernardIE5317

Thank You for your kind assistance. Modified code so std::optional is no longer utilized.

C++20

Problems using std::span<char>

6 Sep 2022 by Jörn Kastner

I'm trying to use std::span to use both legacy C arrays and std::strings. Problem is that I can't "clear" spans correctly. Am I missing something? What I have tried: Consider the following code: void ClearSpan(std::span...

C++20

How to convert system command output to string ?

19 Oct 2022 by Death Smoke

I Want to convert the output of this code to string type , but i cant make it. #pragma warning(disable : 4996) #include int main() { char cmd[10]; strcpy(cmd, "dir"); system(cmd); } What I have tried: I tried to...

How to delete a key from the registry using C++ ?

25 Oct 2022 by Michael Haephrati

In the code below you can see how to delete a subkey or the entiry key HKEY hKey = NULL; long lReturn = RegOpenKeyEx( HKEY_USERS. _T("folder \folder\ folder\{Key name}"), 0L, ...

What is the evaluation of overloaded operators in an expression?

29 Oct 2022 by Utkarsh Singh Rajawat

Like let's say - A a1,a2,a3,a4; a1=a2*a3+a1++/2; Assuming there is a class A and *,+,post increment operator(++) and / are overloaded in class A. a1,a2,a3,a4 are objects of A class. So what's the order of evaluation of operators in above...

C++20

overloading

What is the evaluation of overloaded operators in an expression?

29 Oct 2022 by OriginalGriff

That's tricky ... Why Does x = ++x + x++ Give Me the Wrong Answer?[^]

C++20

overloading

What is the evaluation of overloaded operators in an expression?

29 Oct 2022 by Richard MacCutchan

See also C++ Operator Precedence - cppreference.com[^].

C++20

overloading

What is the evaluation of overloaded operators in an expression?

29 Oct 2022 by Greg Utas

Whether they've been overloaded or not, the compiler generates code to execute operators in the same order. If you read the page that Richard linked, I think you'll discover that you're mistaken about the order in which the evaluation occurs for...

C++20

overloading

How do i...how to resolve compile error re / template parameter shadowing

5 Nov 2022 by BernardIE5317

Greetings Kind Regards The routines below do not compile w/ error messages shown. I am mostly interested in the first routine assert_Search_results The error refers to a template parameter being shadowed. I do not know what that means. I seek...

C++20

templates

How do i...how to resolve compile error re / template parameter shadowing

4 Nov 2022 by Richard MacCutchan

This is the same question as How to resolve compile error re/ shadowing of template parameter whatever that may be[^]. Please do not repost.

C++20

templates

How to utiize C++20 std::format by name?

13 Nov 2022 by BernardIE5317

Greetings Kind Regards I am attempting to utilize C++ std::format and pass the format string by name. However this results in compile error as shown below. I have a very long format string and do not wish to stick it in the call site. I do not...

C++20

formatting

How to utiize C++20 std::format by name?

13 Nov 2022 by Richard MacCutchan

The format string must be a constant expression, see std::format - cppreference.com[^]. [edit] I have been looking at the documentation (per the above link), and trying some tests. Even using the string: const char* fmt = "{}"; produces the...

C++20

formatting

C++20 template specialization

24 Dec 2022 by hans.sch

I'm trying to understand template specialization in modern C++. The code makes no sense, it is only a proof of concept. (Or rather, a disproof until now.) template struct xyz { static size_t const data = 0; }; template

C++20

[Solved] why I cannot properly overload an operator with a templated param?

17 Mar 2023 by Phoenix Liveon

How do we properly create an overloaded operator specifically this "

[Solved] why I cannot properly overload an operator with a templated param?

17 Mar 2023 by klarrra

Find some good help here. https://kbrown.hashnode.dev/c-in-computer-science

How to fix infinite loop with a WINAPI function?

27 Mar 2023 by RexyCode

I'm trying to code a timeout function that kicks out the user if he doesn't select any options in a given amount of time. However I'm finding myself stuck in a infinite loop and even my wait timer can't destroy the loop. My code: namespace jsw...

C++20

timer

API

How to fix infinite loop with a WINAPI function?

27 Mar 2023 by Mircea Neacsu

The wait function is OK. It's the main loop logic that is not right. The do...while loop has nothing to break it as the wait function is outside the loop. This should work: int main () { using namespace jsw::threading; int option{}; ...

C++20

timer

API

Can you make a timer thread work with multiple switch/case statements?

7 Apr 2023 by RexyCode

I'm trying to code a time out "function" that can work in a nested switch and case statement. However my problem is the following, the first switch/case works like expected, on the other hand, the second switch doesn't work in any way. My...

C++20

timer

API

explicit(To Be || !(To Be)) - Discussion and Usage of explicit(bool) C++20

22 Apr 2023 by Coral Kashri

More about explicit(bool) C++20

C++20

C++

The Mystery of the Missing Bytes

22 Apr 2023 by Coral Kashri

In this article you will see how to save bytes and alignment when containing some types inside a structure.

C++20

bytes

C++ Helps Your Compiler to Help You

22 Apr 2023 by Coral Kashri

How compiler helps code run faster and generates warnings in single cross-compiler way

C++20

compiler

Maintain Your Iterations – Iterators Customization – Part 3

23 Apr 2023 by Coral Kashri

Iterators Customization

C++20

C++

The View of the String - Breaking Down std::string_view

24 Apr 2023 by Coral Kashri

std::string_view can optimize both performance and code readability in code sections which handle strings, but, it can also lead to UB and memory issues if used incorrectly.

C++20

C++

How do I write the algorithm of the question said to write a C++ program to read five integer elements into an array and find their sum "

30 Jun 2023 by AAisha Sultan Salim Al Kindi

who can i write a algorithm to the question the question said: To write a C++ program to read five integer elements into an array and find their sum please help me to write the algorithm What I have tried: I WRITE THE CODE OF THE QUESTION ...

C++20

C++20 constrained auto&& not a "universal reference"

18 Jan 2024 by Member 14620282

"auto&&" preceded by concept "con" is not a "universal reference as shown below. Remove the constraint by changing "con auto&&" to "auto&&" and it is a "universal reference" (no compilation error). Could someone please explain why? ...

C++20

C++20 constrained auto&& not a "universal reference"

19 Jan 2024 by Maxim Kartavenkov

In your code: template concept con = std::is_class_v && std::derived_from; I guess should be Base instead of base

C++20

How should go about this inventory system?

21 Jan 2024 by Brennon Nevels

I'm in the midst of building a text-based game with hope I can implement an inventory system among other things to make the world interactive. I have already created an item class: enum ItemRange { ShortRange, MidRange, LongRange,...

C++20

* *** ***** *** *

29 Feb 2024 by Richard MacCutchan

Sorry, this site is not here to do your work for you.

C++20

libpe: PE32/PE32+ Binaries Parsing Library

17 Mar 2024 by Jovibor

Library for parsing internal structures of PE32/PE32+ binary files.

Hex Control for C++/Win32 Applications

14 Dec 2022 by Jovibor

Fully featured Hex Control written in C++/MFC

C++14/20 Heterogeneous Lookup Benchmark

18 Jan 2021 by Shao Voon Wong

Heterogeneous lookup with char* and string_view without temporary string instantiation in ordered and unordered containers

C++14

C++20

C++

C++20, module declaration & definition unit for templated logic

25 Jan 2022 by Stefan_Lang

I have read, but didn't understand a word of, your question. In the topic header you mention templates, so the only advice I can offer is check out this guide: https://itnext.io/c-20-modules-complete-guide-ae741ddbae3d[^] The section Quote:...

Wild West Coding: E.B.C.O. Compression

28 Aug 2021 by RegularJoe5150

A reformulation of compressed pair into a type list

How to convert system command output to string ?

19 Oct 2022 by CPallini

Are you possibly searching for popen? See, for instance: The Marvelous popen() Function | C For Dummies Blog[^]

How do I get this code to work

17 Sep 2023 by Richard MacCutchan

Had you read the error message you would see that line 19 has an illegla character. std::ctime(¤tTime), Also, there is no variable named tTime; you most likely meant currentTime. And the macros _FILE_ and _LINE_ are incorrect, they take double...

C++20

How to delete a key from the registry using C++ ?

27 Oct 2022 by Death Smoke

Hi all, I Searched how to delete a whole key from the Registry using c++ anyone here can help me because i didnt find any clear example about this subject. the key path is like here : Computer\HKEY_USERS\folder \folder\ folder\{Key name}. So...

AVL Databases Have Finally Arrived

7 Feb 2023 by Ben McNamara

I++ contains AVL databases

C++20

C++

Why this udp socket not work when I run it in pc outside the network ?

16 Mar 2024 by Line Item

I would try running this from a command line, with some adjustments for that to make it a simple command. Get that to work then add to that a little at a time. Maybe then try moving that to PowerShell. Get that to work then add more until you...

The answer to the equation

28 Apr 2021 by rosmary404

I have the answer to this equation in Pascal. Can anyone help me convert this to c or c ++? equation: y1+y2+y3+y4=12 yi ≥ 0 , 0 ≤ i ≤ 4 pascal code (but i cant run it) : program selections3 (input,output); var x1,x2,x3: integer; begin for x1...

Getting todolist to work on new windows PC

3 Jul 2021 by Member 15274803

Thanks for a great product. I bought a new PC (windows 10 64 bit) and it won't run, saying it needs MS Visual C++ 2010. The link to download MS Visual C++ 2010 is broken. I am also thinking a later version of MS Visual C++ should work. Can...

C++20

Why is the base class public method not found?

3 Jul 2021 by BernardIE5317

My thanks to dead.rubber.chicken for directing me to the language rule which I must accept so will utilize using directive to solve problem but still do not understand why the language refuses to support what seems a logical extension to the...

C++20

Unable to get user input in the day 1 problem of advent of code 2022

5 Dec 2022 by Harsh 5

The question is straightforward but the only thing I cannot conquer is getting the elf's calorie data as input from the user. I have to read for a new line and whenever I get a new line I have to update my sum to the maximum calorie/sum an elf...

How do I simulate the interaction of two point masses(gravitational pull) using the verlet algorithm?

21 Nov 2021 by OriginalGriff

Compiling does not mean your code is right! :laugh: Think of the development process as writing an email: compiling successfully means that you wrote the email in the right language - English, rather than German for example - not that the email...

C++20

C++20, module declaration & definition unit for templated logic

27 Jan 2022 by Phoenix Liveon

The problem was I cannot properly separate the declaration & definition of a templated symbols such as classes, structs, functions, and many more. Before we could continue I have this quick statement on how I organized my work/project. We can...

How do I write the algorithm of the question said to write a C++ program to read five integer elements into an array and find their sum "

30 Jun 2023 by Member 16040932

#include using namespace std; int main(){ int arr[5];int sum = 0; for(int i = 0 ;i>arr[i]; sum+=arr[i]; //short and efficient code; } cout

C++20