Beginners - C++ Forum

Welcome to the beginner's forum in C++.com! In this forum, users can to talk about any topic related to C++ for non-expert audiences. Feel free to participate...

[2 replies] Last: How To Answer Questions in a Helpful Way Be gentle. Problem-relat... (by admin)

by Zolaboony

Console Closing Down (1,2,3,4,5,6,7)

Hi, i am new to C++ and have just written my "Hello World" program. It worked all right but the console/cmd closes down instantly. If you tell me why it is clos...

[120 replies] Last: It displayed "Hello world" after you pressed Enter. int c is a ... (by Duthomhas)

by Cyclone

Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is...

Hi, I am getting an error when I run my program. the error is... Unhandled Exception: System.AccessViolationException: Attempted to read or write prote...

[14 replies] Last: so salem c is correct. The problem came back. It seems a bit random, s... (by Cyclone)

by Jonathan100

Git problem

Hi. I am trying to get out a confused git situation. I can't really remember how I got there, but I want to get out and manage to add, commit and push like bef...

[2 replies] Last: A meta-search for git push/pull errors and possible solutions: https:... (by George PlusPlus)

by Mif

C programming. Using uninitialized memory warning.

I keep getting this warning even I initialize the memory, then I double-check the code paths to ensure no element in allNodes or closedSet is accessed before al...

[14 replies] Last: ... (by Duthomhas)

by cgm2k7

Reading files with fread() in chunks.

Good morning everyone! I would like to ask for a little help here on the forum. It's like this. I have a binary file of (9175867 bytes), I need to read only (...

[18 replies] Last: Just wait for when you have EVERY post reported, including ones that p... (by George PlusPlus)

by demhat

function declaration with MACROs

hi guys as I know function declarations are like this: void ClearBackground(Color color); however sometimes I can face some kind of function decl...

[7 replies] Last: And, for one question within the OP: Yes, there can be more than just ... (by keskiverto)

by PhysicsIsFun

MPI runtime weird example

Hi guys, I have a weird mpi example where I don't understand the used runtimes. #include <iostream> #include <mpi.h> #include <chrono> #include <cmath> void...

[1 reply] : its hard to know what is really going on with caches, other processes,... (by jonnin)

by zzzhhh

Why do I have to surround parentheses in this fold expression?

template<typename... Args> void printVariadic(Args... args) { (... , (std::cout << args << ' ')); } printVariadic(1, 2, 3, 4); This code can compile and p...

[1 reply] : Because the standard defines a unary left fold expression as: ( ...... (by Peter87)

by salem c

need some help

That seems pretty close to being right, why don't you post the whole program? In case anyone stumbles on this nonsense, the original post / author got sh-canne...

[11 replies] Last: George, I would avoid directly hyperlinking the profile, if you don't ... (by Ganado)

by colt

Simple tga writer not working correctly.

Hi. I did write code to write a simple tga file format file. Unfortunately, it does not seem to work as expected. The resulting image is always black, not ma...

[3 replies] Last: You might consider finding an already existing 3rd party library and u... (by George PlusPlus)

by Bengbers

Namespace std not recognized in public API.h for shared library (1,2)

It has been quite a while since I was working intermittently on my project to write a C++ shared library for Basex. I finally managed to create a working combin...

[21 replies] Last: smart pointers are used as an 'owning' pointer. They 'own' the allocat... (by seeplus)

by Jonathan100

Segmentation fault (core dumped)

Hi, I get strange segfault error when working with hierarchy of c programs (3 stages) I can give a link to the sources, but first i will describe the issue: i ...

[6 replies] Last: Thanks folks, the error was due to a buffer overflow of char array I ... (by Jonathan100)

by zzzhhh

It is known that we can't initialize rvalue reference with lvalue, but why can function name?

It is said that we can't initialize an rvalue reference with an lvalue. For example: int i=0; int && irr = std::move(i); int && irr2 = irr; In the above code,...

[5 replies] Last: And the standard you cited is two floors above: "http://eel.is/c++dra... (by mbozzi)

by zzzhhh

Why is const gone in the return type?

template <typename T> const T&& Test(T&& t) { return t; } ...... int i = 0; int&& irr = std::move(i); decltype(Test(irr)) t = i; Since there is a `const` ...

[5 replies] Last: @Peter87: Thank you for referring me to the relevant Standard. I think... (by zzzhhh)

by bkelly13

Convert binary to base 58

I want to convert a long binary number, 256 bits, into a base 58 char array using c code. I cannot find a simple explanation. The Bing tool insists on convert...

[10 replies] Last: I get the same result on those 2 sites (dcode only accepts decimal inp... (by DizzyDon)

by Ch1156

Best way to modify a variable in a class (1,2,3,4)

So whats the best way to modify a variable in a class? Below I have a version that does so through a pointer, but is it better to just make a function that modi...

[63 replies] Last: I suggest you look into OOP class design using UML etc. This will give... (by seeplus)

by learner999

Finding minimum element of a tuple on the basis of first element

Hello everyone, I do not know, if it is possible to find the minimum first element in a tuple without using sort function. I have a tuple like this : data=[...

[5 replies] Last: I have a tuple like this : data=[ ( 23, a, 3.78, d), ( 11, x, 5.8, w)... (by seeplus)

by zzzhhh

Which ctor of std::unique_ptr is used, when there is a user-defined deleter which is a function?

Following is excerpted from section 12.1.5 of text "C++ Primer", which contains text and code constructing `std::unique_ptr` with a user-defined deleter which i...

[1 reply] : The code calls constructor 3 or 4. When the cppreference page writes ... (by Peter87)

by Brian845

txt file to vector giving wrong values

I'm loading a txt file into a vector using the code I've written below. It works great except for one BIG issue i'm having. First I'll give a very small exampl...

[11 replies] Last: There's a good (and free) set of C++ tutorials and lessons available o... (by George PlusPlus)