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 Bengbers

Namespace std not recognized in public API.h for shared library

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...

[18 replies] Last: double free or corruption You could be trying to free memory after... (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)

by zzzhhh

Why can't assign an overloaded function to std::function?

int add(int i, int j) { return i + j; } std::string add(const std::string& s1, const std::string& s2) { return s1 + s2; } ... std::function<int(int, int)>...

[1 reply] : There is a constructor template and a class template in play here, and... (by mbozzi)

by SubZeroWins

C++ Questions (1,2,3,...,10,11,12,13)

1) Why does "&myChar " act differently in 2 different contexts? char* pointer = &myChar ; //ALSO WORKS!!! Above, it actually return the address of ...

[246 replies] Last: I agree with the search fiasco and the current state, but it does leav... (by SubZeroWins)

by Ch1156

When to use const class member variables? (1,2)

So while doing something, I made a member of my class const, and i got errors, upon some cursory research I found i need a copy constructor, and to define my ow...

[21 replies] Last: Ok, so its perfectly ok to use static const, and to make it non copyab... (by Ch1156)

by Jonathan100

lest shift an u8 array

Hi. I have an exsiting u8 array in a function (function that get u16 array as argument). How can i create a new u16 array the starts from 3th byte of an existi...

[2 replies] Last: what you had is probably close. remember that c++ starts at zero. th... (by jonnin)

by hassan236

const keyword in function declaration

#include <iostream> #include <iomanip> using namespace std; const int NUMCOLS=4; const int TBLlROWS = 3; const int TBL2ROWS = 4; void showArray ( const...

[2 replies] Last: thanks buddy (by hassan236)

by PhysicsIsFun

size_t implicit conversion

Greetings! I have a loop that doesn't want to break when it should. for (int i = Xdata.size() - 1; i >= Xdata.size()-B; --i){ // loop body ...

[17 replies] Last: I swear I’m getting senile. I'm getting there first. :|... (by George PlusPlus)

by CodeChaser

operator const char* return (1,2)

Hi y'all i was wondering if i can have something like this on one line? return (ss.str().c_str()); or return ((ss.str()).c_str()); operator co...

[39 replies] Last: If I were to start using command-line compilation I would probably go ... (by George PlusPlus)

by nvthielen

ASM code and C++

Hallo, cplusplus. i am trying to get a bios interrupt call to the bios in c++. but compiling it i get a error.. kernel.c:27:9: warning: implicit declar...

[3 replies] Last: OP is clearly not messing with programming on modern systems. Hints: ... (by Duthomhas)

by BigNibs

Looking for tutor for OOP class

Hi everyone, I dont know if this is the right channel to ask this but im starting to fall behind pretty hard in my OOP class, I really need to catch up on a cou...

[3 replies] Last: I can help you out with what I know currently. Tag me if you are inter... (by CodeChaser)