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General C++ Programming - May 2021

How to store cell values of date and numbers in local variables using xlnt library for C++

I am trying to read different cell values from a excel worksheet using the xlnt library for C++ provided at: https://github.com/tfussell/xlnt . The code that i ...

[1 reply] : does this work? int x = stoi(cell.to_str()); or double d = stod(cell... (by jonnin)

by JamieAl

OpenMp: Parallel code takes longer to run than serial code?

I have a serial code with simple forward FFT function and other functions, in the main code a basic for loop for initialization purposes. This code is a much sm...

[8 replies] Last: nah that 1 thread run isnt random. its likely it cached something afte... (by jonnin)

by uppercaseguy

sdl program not restarting

i have literally spent all night trying to ask the user to if he wants to play again pres enter, and when he does press enter, the game restarts but i guess som...

[1 reply] : debug it, step through what all your variables are in the second run. ... (by jonnin)

by zerophase

Is there a means of redefining free functions?

I'm writing some unit tests for some extension methods, and some of the other extension methods call each other. The only problem is my fake extension methods o...

[1 reply] : yes, you seek preprocessor, look up an example of #ifdef -- it forms a... (by jonnin)

by Mitsuru

Failure of boost::geometry::within for polygons

Dear experts As this title, I failed boost::geometry::within, some are succeeded but the others are failed. I wonder if boost::geometry::within has specif...

[2 replies] Last: @Mitsuru, when you say "failed", what do you mean? Can you give examp... (by lastchance)

by hentaimean

Dynamic programming. Recursion. Loops.

Hello! Please tell me how to implement an algorithm with recursion using loops. "main.cpp" #include<iostream> #include "methods.h" int N, M, *a, **mas_r...

[13 replies] Last: Oh, thanks a lot!) (by hentaimean)

by dkaip

Remove duplicates of vector problem

Hello. I have the classic remove duplicates of vector. At line remove_duplicates(channels); compiler say channel has no member url. struct channel { ...

[4 replies] Last: Thank you. Finally code. std::vector<channel> channels; te... (by dkaip)

by Laiter

Connectionless p2p library

I'm looking for a simple library that allows me to send packets between pc's using their IP and without establishing a connection between them. Also it would...

[2 replies] Last: In that same vein try "socket programming C++" searches if you haven't... (by againtry)

by JUANDENT

In C++20, <chrono> has been extended by the Howard Hinant date library but some things are missing

Hi, Although it is nice that <chrono> has been extended, there are some functions that I haven't found after looking intensely... For example conversion f...

[3 replies] Last: C++ version support for the major compilers is at https://en.cpprefere... (by seeplus)

by BoomerDev

Is there/What is the C++ version of the strlen function?

Hello there, I was working on my game engine's string class when I ran into an error while trying to compile on Linux (I normally compile with MSVC). The compil...

[2 replies] Last: some decades ago, c++ stuffed all the standard stuff into namespaces a... (by jonnin)

by coff33Cup

Vector of objects

Hey ya'll I'm new to vectors and I have created a class of PaintJobContracts, which should have fields for a customer's name, job number, and amount owed. I wen...

[4 replies] Last: Hello coff33Cup, keskiverto has a very good answer. I take a more ... (by Handy Andy)

by seeplus

VS2019 16.10 constexpr

VS2019 16.10 is supposed to include support for the C++20 constexpr for std::string and std::vector. So why doesn't this work? What have I overlooked?? #incl...

[5 replies] Last: OK. So for compile time definition, you can use constexpr with std:arr... (by seeplus)

by JamieAl

FFTW plans using OpenMP

I have the following function using the FFTW3 plan and I am trying to parallelize it with openMP. I am following with the FFTW doucmentation, however I don't th...

[3 replies] Last: This declaration has no storage class or type specifier at line 8 h... (by againtry)

by Zaneemma2021

Programming and data structure

Implement an unbounded double-ended Queue (using the single or double-linked list) as a template structure (aimed at storing values of any type), and the...

[1 reply] : I did not have time to read your code closely. However, based on a qu... (by doug4)

by mist3

Storing multi-character character in an array

Hello, I'm having trouble storing non-english letters (ą, č, ū) in a char array. It does store them in a normal char array, but takes up two spaces (ex. char...

[2 replies] Last: instead of std::string s; say std::u16string s; char16_t instead o... (by jonnin)

by bartuaslan

Implementation of Sorting Algorithms

You should write a program to sort an array. For this purpose you will implement two sorting algorithms: Insertion Sort and Merge Sort. For each algorithm, you ...

[10 replies] Last: ^^ this is more important than it seems at first. When I started, I ... (by jonnin)

by RicoJ

Why do I have to assign a {} expression to an object?

I'm playing around the bracket list expression, and I got an error error: expected ‘;’ before ‘}’ token when running this: int main() { {1,2,3...

[3 replies] Last: And in case you're specifically after a legalese type of answer, the s... (by Ganado)

by axl

Extract certain integers from string and add them.

Hello, so I'm a little stuck with trying to solve this problem out. The task I face is to read through the string numbers and decide what the greatest sum is ...

[3 replies] Last: #include <iostream> #include <string> int bigSum(const std::string&... (by seeplus)

by theguyy

SDL music and event que doesnt sync properly

currently i am creating a main menu for a game in which I want a background music played and a different one when the game actual starts, the game starts by pr...

[3 replies] Last: Please don't update code in previous posts. Now @salem c's response m... (by doug4)

by adam2016

Simulating Nodes on a network.

Hi guys, So this is probably a basic networking question, I want to write a script that will simulate nodes on a network. I could set up a number of virtual ma...

[2 replies] Last: Thanks salem :) Never thought about the above points (by adam2016)

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