Questions tagged [c++20]
Code that is written to the 2020 version of the C++ standard. Use in conjunction with the 'c++' tag.
193
questions
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C++ Hash table, Hash function, benchmark vs std::unordered_set and std::hash
I wrote my own hash function and my own hash table.
My hash function seems to work surprisingly well!
Feel free to comment anything!
Hash function:
...
- 1,181
2
votes
1
answer
37
views
C++ Doubly linked list, including benchmark vs std::list
I wrote a rudimentary implementation of doubly linked list.
Feel free to comment anything!
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- 1,181
2
votes
1
answer
56
views
C++20 Multi-queue Thread Pool with Work Stealing
This is a follow up to my previous post which also follows up on my first post regarding my thread pool implementation. I have since made some further changes and attempted to improve performance with ...
- 410
1
vote
1
answer
60
views
Using std::variant with std::ranges algorithms
I have some predicate objects that take some value and return the result of some criteria. (My real implementation is more complex, this is only a minimal example):
Run on Compiler Explorer
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- 125
1
vote
1
answer
94
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Storing different types with common base using atomic-based typeid
I'm trying to develop some kind of in-memory store for my entities. These entities are representations of the devices available on the system. There may be eg. 3 leds, 1 temp sensor, 2 engines etc. ...
- 241
2
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1
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41
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UPDATE #1: Lengthening the time it takes to access files using function hooking
https://github.com/speedrun-program/load_extender
This is the previous post: Lengthening the time it takes to access files using function hooking
I tried adding everything from the previous post's ...
2
votes
1
answer
53
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Lengthening the time it takes to access files using function hooking
https://github.com/speedrun-program/load_extender
This is something I made and posted here about a year ago, but I decided to remake it.
To compile this on Windows, you need to install EasyHook.
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0
votes
1
answer
21
views
C++20 Wrapper class for an unsigned integer type and a templated derived class that codes modular arithmetic type
The context is a library to represent numbers (in this case integers) by wheighted position by radix powers for every radix R, passed as template argument. These derived types are digits of radix R, ...
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1
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1
answer
45
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Verified downcasting if RTTI is active
In an application that uses heavily polymorphic classes, I have often the need to downcast a pointer or a reference to the correct derived class. They should always be of the correct derived class, ...
- 188
1
vote
1
answer
90
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C++ merge sort, logging, unit test, performance check
I wrote a merge sort implementation in C++ today in C++20 way.
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- 1,181
21
votes
6
answers
8k
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I created something much faster than a std::string
I've recreated std::string in a way that might be faster.
System Features:
Much faster than std::string.
Easy to use.
It was designed as part of a large database ...
- 351
1
vote
1
answer
68
views
Yet another command / event dispatcher
I'm trying to implement some kind of command dispatcher.
I've already developed some code, but I'm not sure about a few things.
My dispatcher is a simple command dispatcher, so for each command, there ...
- 241
3
votes
1
answer
121
views
Mapping between Enum <-> Enum <-> String view
I've been working on some kind of mapper that would allow me to map between types.
My objectives:
it should allow mapping between two enums
it should allow mapping enum to string_view
it should allow ...
- 241
4
votes
2
answers
141
views
C++20 Single Queue Thread Pool
This is a follow up to my previous post. I've made a number of improvements to the thread pool and corrected some bugs as well.
The most up to date version of the code is available on my Github.
I ...
- 410
4
votes
1
answer
120
views
Searching for a performance bug in a C++20 pathfinding algorithm (NBA*)
(See the next iteration.)
I have this pathfinding algorithm:
DirectedGraph.hpp
...
- 25.3k
3
votes
1
answer
45
views
checked conversion function for C++20
Similar to C++ int_cast<> function for checked casts?, but C++20, and with target type deduced from context.
The goal is to implement a runtime check that the value being converted can be ...
- 183
3
votes
1
answer
71
views
function template for string_view-to-integer conversion
I want to make the following function a function template that supports all the integral types:
...
- 213
1
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1
answer
31
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5
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3
answers
405
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generic implementation of median
Below is a generic implementation of the summary statistics function Median.
Discussion of efficient use of std::nth_element and ...
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0
votes
1
answer
44
views
Class accepting data input by variable, function pointer or lambda
Background
I am writing a library that takes some data from the user and works with it. I was experimenting with ways to allow users to provide the data by the following methods:
As a (global) ...
- 103
1
vote
1
answer
79
views
Strong typing -> Named type
I'm trying to generate a strong(er) type wrapper for C++. I've seen the NamedType by Jonathan Boccara, but I want a slightly different behavior.
Ideally I would be ...
- 424
6
votes
3
answers
655
views
14
votes
2
answers
1k
views
Block-free priority lock
Background
I wanted to write an event loop that supports scheduling, but found that no implementation of priority queue that I know of supports waiting on a condition variable (the idea is that the ...
- 9,049
2
votes
1
answer
75
views
An rough implementation of `std::is_constructible`
As a challenge/fun activity/task, I have implemented my version of std::is_constructible.
Here is the source code:
...
5
votes
4
answers
2k
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C++ basic bank money class
I am trying to create a basic money class that fits into a small console banking application I am making.
Money.h
...
- 53
2
votes
2
answers
79
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Checking image size in C++
This is a follow-up question for 3D Inverse Discrete Cosine Transformation Implementation in C++. After checking G. Sliepen's answer, I am trying to update the part of width and height checking of <...
- 3,302
6
votes
4
answers
295
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Nelder-Mead optimization in C++
I've implemented the Nelder-Mead optimization algorithm in C++. I found this document to be a very good explanation of how the algorithm works, but I'll try my best to explain it (with an example) ...
- 12.2k
2
votes
0
answers
57
views
invocable_traits v5
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members are also callable, those should be handled (and be considered 0-...
1
vote
1
answer
60
views
invocable_traits v4
Update: there is a new version of this code: v5 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members ...
3
votes
0
answers
42
views
invocable_traits v3
Update: there is a new version of this code: v4 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members ...
1
vote
1
answer
41
views
c++ multithreaded message broadcaster with link lifetime management v2
note: This is v2 of code that was previously reviewed.
I have written a class that handles listeners registering callbacks to receive messages. Link lifetime is managed (or is it?). Code is ...
1
vote
1
answer
35
views
c++ multithreaded message broadcaster with link lifetime management
note: A version of this code without link lifetime management was previously reviewed. Adding lifetime management actually made the code simpler, and the class simpler to use.
I have written a class ...
3
votes
1
answer
46
views
invocable_traits
Update: there are new versions of this code: v3 is posted here and v4 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since ...
2
votes
1
answer
69
views
callable_traits implementation
Update: there are new versions of this code: v2 is posted here, v3 is posted here and v4 is posted here
Goal: implement traits that for anything callable return its arity, return type and the ...
0
votes
1
answer
49
views
Advent of Code 2021 Day 4: Play Bingo against a Giant Squid
[This is my first post here - though I have been lurking in the back reading, plussing, and hopefully learning for over two years]
Below is my solution for Advent of Code 2021 Day 4, where you are ...
- 188
9
votes
1
answer
445
views
3D Inverse Discrete Cosine Transformation Implementation in C++
This is a follow-up question for 3D Discrete Cosine Transformation Implementation in C++. In this post, I am trying to follow user17732522's answer to update ...
- 3,302
2
votes
1
answer
137
views
c++20 compile time string utility v2
This is a follow up on c++20 compile time string utility, as suggested by G. Sliepen posted as a new question, so it can be reviewed on its own.
The following code has suggested improvements from the ...
- 65
6
votes
1
answer
211
views
3D Discrete Cosine Transformation Implementation in C++
This is a follow-up question for Parallel 3D Discrete Cosine Transformation Implementation in Matlab and Operator overloading in Image class implementation in C++. I am trying to implement 3D Discrete ...
- 3,302
1
vote
1
answer
62
views
next/prev function for a circular array
This is a next/prev function for use in a circular array. What do you think?
...
- 1,354
2
votes
1
answer
110
views
Operator overloading in Image class implementation in C++
This is a follow-up question for Dictionary based non-local mean implementation in C++. There are some issues about operators (operator+ and ...
- 3,302
4
votes
2
answers
333
views
c++20 compile time string utility
While upgrading some meta-program running in production for years to the latest (c++20) standard, I rewrote this particular compile time string utility.
Even though this new version produces desired ...
- 65
7
votes
5
answers
917
views
Checking whether a string is a permutation of a palindrome in C++20 - follow-up
This post is the follow-up of Checking whether a string is a permutation of a palindrome in C++20.
So, what's new? Well, nothing else except that the procedure is now generic and accepts all ...
- 25.3k
3
votes
1
answer
105
views
Dictionary based non-local mean implementation in C++
This is a follow-up question for Manhattan distance calculation between two images in C++ and Dictionary based non-local mean implementation in Matlab. For learning C++20 and researching purposes, I ...
- 3,302
2
votes
0
answers
150
views
2d Grid - Iterating by Rows / Cells - Take #3
Edited with a bit more unit tests.
Preface
Following my second version:
2d Grid - Iterating by Rows / Cells - Take #2
I believe that I am now satisfied with this new version below.
There is still one ...
- 122
10
votes
4
answers
1k
views
Checking whether a string is a permutation of a palindrome in C++20
(See the next iteration/follow-up here.)
I have this short function is_permutation_palindrome, which returns true only if the ...
- 25.3k
7
votes
3
answers
861
views
Checking for NaN bit patterns in C++
I live in hostile environments (GCC and Clang) which remove calls to isnan which prevents me to perform validation of my input before running computations.
Here is ...
3
votes
2
answers
153
views
Manhattan distance calculation between two images in C++
This is a follow-up question for Two dimensional gaussian image generator in C++ and Image pixelwise operation function with multiple inputs in C++. For learning C++20 and researching purposes, I am ...
- 3,302
3
votes
0
answers
144
views
Implementation of Dynamic Array with allocators and C++20
To train my skills in C++, I decided to implement the well-known "Dynamic array" data structure on my own. I realized early on that using pointers or smart pointers is wrong, as it leads to ...
- 131
2
votes
2
answers
110
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2d Grid - Iterating by Rows / Cells - Take #2
Preface
Following my first POC version:
2d Grid - Iterating by Rows / Cells
I have gained much more understanding, and present
A new version
A new version is ready, with templates and an attempt at ...
- 122
3
votes
0
answers
73
views
Order guaranteed recursive_transform template function implementation with execution policy in C++
This is a follow-up question for A recursive_transform Template Function with Execution Policy, A recursive_transform Template Function Implementation with std::invocable Concept and Execution Policy ...
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