General C++ Programming - August 2020 (Page 3)

by vtee2014

I have been researching the details of the following struct definition and I have some questions that have been hard to clarify. This came from a source focuse...

[4 replies] Last: where I assumed the 'C' in '<C>' was a placeholder.... I'm not sure ... (by MikeyBoy)

by bibo

Regex error: Parenthesis is not closed.

int main() { string integer = "(\+|-|\0)[0-9]([0-9]{*})"; //string d1 = "("+integer+"."+"([0-9]{*})"+")"; //string d2 = "("+integer+"e"+i...

[5 replies] Last: #include <string> #include <iostream> #include <regex> #include <algo... (by dhayden)

by dev1243

cant get it to read the text files and display the txt help

#include <string> #include <iostream> #include <vector> #include <fstream> using namespace std; class Question { private: string...

[2 replies] Last: cant get it to read the text files and display the txt help Without... (by dhayden)

by fewdiefie

race condition

Hi! how do I make the following program print numbers in the correct order like this: 0 1 2 ... 100 #include <iostream> #include <thread> int x = 0; void fo...

[6 replies] Last: #include <iostream> #include <thread> #include <mutex> int x = 0; st... (by dhayden)

by Ganado

Struct pointer conversion, possible undefined behavior?

I found a place where some weird casting was happening, and I wanted to confirm if someone knew it was legal. // Example program #include <iostream> struct S...

[9 replies] Last: Cubbi: Okay, that's starting to make more sense. I didn't realize the ... (by Ganado)

by plexus

Weighted random distribution

Hi all, I'm trying to generate the numbers 0 .. 9 in a random fashion but with different probabilities for the individual digits. The distribution comes f...

[16 replies] Last: A class based approach to encapsulating <random>/<chrono> is a valid... (by deleted account xyzzy)

by jpweldon

Debug C main program

I need assistance in debugging a not-very-large C main program. Reason(s) for the crash are not evident to one who is not a professional programmer. I am using ...

[2 replies] Last: if its small, you can get solid free help here. Can't hurt to throw ... (by jonnin)

by stav

vector of incomplete type UB still?

Hi, i read this article https://www.drdobbs.com/the-standard-librarian-containers-of-inc/184403814 that explains why its undefined behavior to instantiate a STL...

[1 reply] : So i think i've found the answer here https://en.cppreference.com/w/cp... (by stav)

by AJS248

Need some help with int/ double input error checkings

I'd like to put a condition for a 'double variable.' For example: cin1: double var1; cin >> var1; (How can I code if var1 is not a number, then execute...

[5 replies] Last: #include <iostream> #include <sstream> #include <string> using namesp... (by lastchance)

by Scarletpimp

openssl base64 decode function is not working for specfic string

I have the below openssl code to decode json content, it works fine if the encoded data is "eyJ0ZXN0MSI6eyJ2YWwyIjotOTEuNiwidmFsMyI6NDAuMTIzNH19" but it does n...

[6 replies] Last: yes i will pad it with "=" before decoding, Thanks a lot for clarifyin... (by Scarletpimp)

by nockson

i need some help

During this period of lockdown, many people started to play different games at their homes since they could not go outside. One of the simplest games is Play_W...

[15 replies] Last: Not possible, but you can put the screenshot up on Pinterest or some o... (by againtry)

by Puyol

Black and white kings on the chessboard

Inputting the numbers of the white and black king cells on the chessboard in turn, followed by the natural number N and the sequence N consisting of the numbers...

[2 replies] Last: It’s a trick question because the rules of chess are such that the k... (by againtry)

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