Posts tagged c++
Note: I asked this question on TopAnswers a couple weeks ago, but didn't get any response, so I figured I'd ask it here. I am currently learning C++. I have a parent class (Vehicle) and two subc...
How to write a macro that discards the const qualifier, for any type? I hope some combination of typeof and a cast will do, but haven't found the combination. I tried this, without luck: #define...
The question is about libraries that extend the data type system to ensure physically realistic computations. Think std::chrono but for distance and mass and other things as well as for time. Inste...
For someone who was familiar with C++ in the past and is coming back to it after a long break, what are some useful books that won't waste time with basics but will cover the new features of the mo...
I've heard that in modern C++, smart pointers are preferred to raw pointers for ownership (the so-called RAII principle, as I understand it). This makes sense, and since then I've always used them...
If you have a class which needs to store a construction parameter internally, and you want to take advantage of move semantics, I understand that the parameter should be passed by value: class Foo...
Say we have an abstract class Foo declared as so: class Foo { public: virtual void test() = 0; }; Let's say that we make a derived concrete class FooDerived, and decide to mark it's ve...
Let's say I have a variant that can hold a bunch of different types of values (say I got them from parsing a JSON or similar). using Value = std::variant<std::monostate, int, double, std::strin...
What means the exit code -1073740940 in C++?
Agner Fog has this C++ Vector Class Library, which is ... useful for improving code performance where speed is critical and where the compiler is unable to vectorize the code automatically in an...
We use Jenkins Pipeline to build and test some C++ software. The pipeline script runs the tests on 10 different nodes in a parallel way in order to save time. All of these nodes are real (not virtu...
There is an external program I'm calling from within my C/C++ program, by using fork() and execl(), and redirecting the stdio with dup2() to be able to read the output from the external program. I...
I was trying to plot using following lines in C++. #include "koolplot.h" int main() { plotdata x(-6.0, 6.0); plotdata y = sin(x) + x/5; plot(x, y); return 0; } When I was...
int arr[] = {10,123,14,14,15,16}; cout<<sizeof(arr)/sizeof(arr[0]); I was reading the article. When sizeof() is used with the data types such as int, float, char… etc it simply ret...
#include <iostream> using namespace std; int linearSearch(int array[], int n, int key){ for(int i=0;i<=n;i++){ if(array[i]==key){ return i; } } } int main() { int ...
#include<iostream> using namespace std; class Book{ public: string title; string author; int pages; Book(string aTitle, string aAuthor, int aPages){ aTitle = title; ...
For debugging running programs I often use whatever is integrated with the IDE I am using. QtDeveloper right now, but also used Eclipse, Netbeans and others. Most of them just use gdb under the hoo...
I want to write a text file from multiple threads. The file structure is line-oriented. This means writing of lines should be atomic. I am using Qt 5.15.2. Is it enough to protect a shared QTextSt...
I find myself often writing code like this. try { // code } catch( FailedReadException const & ex) { file.close(); std::cerr << "Read failure " << ex.readFailure() <&...
Is uint8_t guaranteed to be a character type if it exists? Will using a uint8_t* to examine bytes of an object cause violation of the strict aliasing rule? Is the following legal code: #include &l...
Consider an object for which a method is invoked. Beyond certain point the method no longer accesses this at all. No read/writes of non-static members. No invocation of non-static methods. Is it ...
Is it correct to destroy a mutex which is referenced but not owned by an unique_lock as in this code? { std::unique_ptr<std::mutex> mutex = std::make_unique<std::mutex>(); std::u...
tl;dr I'd like to learn a compact, cross-compiler way of selectively suppressing compiler warnings. Consider the case where you really mean to make an exact floating-point comparison using ==, o...
So,I'm having a doubt when I call std:async() on a member function of a class. The book I'm reading says (emphasis mine) You can also pass a pointer to a member function to async(). In that case...
My work tasks have recently started requiring me to use the type_traits header to restrict the classes that may be used in template functions, methods, and classes. And while I used it for a long t...
I'm trying to understand the purpose of the wait() function in Class future<> for C++. At the moment I don't see any purpose for calling wait() instead of get(). What I have tried in code: i...
Is there any guarantee regarding initialization of static and thread_local objects? In example, is there any guarantee about the value printed by the following program? #include<iostream> s...
I'm trying to set up a simple test project, to unit test a change I'm working on. The change is to a file inside some existing project. I've tried to set up the includes as the original has it, but...
I added a QPushButton to my ui file named pushButton, and manually connected it using connect. There are no errors or warnings emitted at any point in the compilation stage The button does show up...
In order to test that coredumps are generated and that they contain useful information which can be retreived with gdb I need to generate a SIGSEGV. Or anything else which causes a coredump. The co...
