Beginners - August 2023

Output Iterators: What does it mean that "we may assign to a given value of an output iterator only once"?

From C++ Primer, Lippman, Section 10.5.1. "The Five Iterator Categories" Output Iterators can be thought of as having complementary functionality to input ite...

[1 reply] : > 1. What does it mean when the author says "we may assign to a given ... (by JLBorges)

by anonomyss

C++ GUI QT (Trafic Light)

I have to write a GUI application for Traffic light - Green/Yellow/Red im allowed to specify the time interval once on the GUI for the colors and it should not ...

[10 replies] Last: Use a QVBoxLayout ? https://doc.qt.io/qt-6/qvboxlayout.html#details... (by kigar64551)

by ElusiveTau

How to write a class that can be written out to ostream_iterator and read from istream_iterator?

I'm reading C++ Primer, Lippman, the chapter on stream iterators and in particular on istream and ostream iterators. For istream iterators: [quote=Lippman]An...

[10 replies] Last: > Can I specify specific input stream types instead of istream& operat... (by JLBorges)

by Feit

Producing a specific pattern

I am trying to produce a specific pattern (shown below) using C programming. I wrote the following code, that does not produce the same output. Would anyone ple...

[3 replies] Last: Many thanks. (by Feit)

by ElusiveTau

How to use extern to refer to an external variable with the same name as variable declared statically?

In the function increment() below, how do I refer to sameName from file2.cpp? main.cpp #include <iostream> #include <string> using std::cout; us...

[3 replies] Last: [quote=JLBorges]This violates ODR I see. I just wanted to understand... (by ElusiveTau)

by spistol

Why CMake doesn't see -std=c++20?

Hi there! I'm trying to install an library. After the "make" command, there are a lot of errors regarding std::chrono. As I see it, it is related to the c++20 ...

[6 replies] Last: If cppreference is to be believed even GCC 13 is not 100% compliant wi... (by deleted account xyzzy)

by raefnal

user adds vector

Anyone know a good method for letting a user add a new vector and access all vectors created...in a menu? I do not have any functional code to post. Any help wi...

[4 replies] Last: As a starter for 10, consider: #include <map> #include <vector> #in... (by seeplus)

by Cyclone

Back Up Microsoft Visual Sudio Project? (1,2)

Hi, Sorry if this is the wrong forum... I am using Microsoft Visual Studio 2019 and would like to know how to make a backup of my project. I need to re-in...

[22 replies] Last: Another way to backup code: Use a NAS (Networked Attached Storage). I ... (by ElusiveTau)

by Ch1156

Does this code look fine

Ive been practicing with using iterators with vectors, vectors of pairs and maps, this happens to be a vector of pairs but it thought i would get it looked at s...

[3 replies] Last: Compare offers a potential use-case for range projections. Could be... (by mbozzi)

by JamieAl

3D C++ array

This feels like a pretty simple question, but I keep getting my indexing incorrect/confused here. Basically, I have these 2D C++ arrays that I am trying to exte...

[3 replies] Last: Have you considered vector<vector<vector<double> > > ? The code will ... (by dhayden)

by Cyclone

An array of vectors

Just wondering how to have an array of vectors. I tried reading this.... https://www.codespeedy.com/array-of-vectors-in-cpp-stl/ I have something like this. ...

[8 replies] Last: Got it working now... I changed using Image = std::vector<char>; ... (by Cyclone)

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