All Questions
10,471
questions
-2
votes
0
answers
27
views
Command exited with non-zero status 124
Given two integers n and x, find the number of triplets (a,b,c) of positive integers such that ab+ac+bc ≤ n and a+b+c ≤ x.
a,b,c are greater than 1. (c is k in my program):
#include <iostream>
...
- 17
0
votes
0
answers
27
views
Extension of lifetime for inner fields when the type's lifetime is extended?
I am pondering about a piece of tooling code that we were using for a while here now, but which I suspect is actual undefined behaviour (at least, I got a couple of debugging sessions where it looks ...
0
votes
0
answers
118
views
const char* vs std::string_view for constants [closed]
I usually use constexpr const char* for defining string constants. Of late, I have been noticing that std::string_view is very popular for this purpose. Which of these is the best?
// 1. char pointer
...
- 437
-3
votes
1
answer
50
views
Optimize memory in operators overload and template structures
The task:
In this task you have to write a structure that will work both like a regular array in C and like a list in Python. Namely, write a structure
template<typename T>
struct FlexArray;
...
-1
votes
0
answers
50
views
<wx/wxprec.h> file not found [duplicate]
I've been trying to learn C++ and I started to learn about GUIs, but I've encountered some problems.
I am using wxWidgets 3.2.5, downloaded it by source on the official website but I can't get It to ...
- 19
1
vote
1
answer
80
views
How do I use std::reference_wrapper to store the reference in an std::unordered_map?
I'm trying to learn the use of std::reference_wrapper and std::ref and the use cases of it.
Here is a sample code I wrote. Please help me solve the compilation error. And it would be great if you can ...
- 13
-1
votes
1
answer
81
views
JNI CallStaticObjectMethod is causing crash with Java 21
The company I work for recently moved to Java 21 from Java 8, which updated the JNI version as well that is used with interoperatibility with C++. All the function (written in C++) called through JNI ...
- 346
-1
votes
0
answers
47
views
Matplot++- dealing with linker errors as a novice
I have installed matplot++ using vcpkg and compiled it with c++17. Working in visual studio 2022, I tried to copy a basic example from its github:
#include <cmath>
#include <matplot/matplot.h&...
- 117
1
vote
1
answer
80
views
What is error: expected unqualified-id before ‘(’ token?
I clone this open source project https://github.com/balfieri/cordic. I encountered issue below after following README to run $ g++ -std=c++17 -o test_basic test_basic.cpp
$ g++ -std=c++17 -o ...
- 51
1
vote
0
answers
69
views
Argument passing and dangling pointers [duplicate]
I know that, in general, when calling a function, the evaluation of the arguments of the function call can happen in any order, but I'm in doubt about this particular situation (imagine T has a move ...
- 11.4k
1
vote
1
answer
90
views
Does early return of the same variable prevent NRVO?
Here is the code:
std::vector<int> foo(bool cond) {
std::vector<int> result;
if (cond) {
return result; // (1)
}
result.push_back(42);
return result; ...
- 6,435
4
votes
1
answer
110
views
correct syntax to access a template variable specialization
assume a template variable in data.h:
template <class T>
struct Data
{
Data() = delete;
Data(T initValue) : value(initValue){}
T value;
};
template<class T>
extern Data<T&...
- 758
2
votes
2
answers
63
views
Partial specialization of a class for pointer to members
I'm trying to create a function object where, given a pointer to a member, it calls std::hash of the pointed-to member (or the result of calling the function member), but there's something wrong about ...
- 11.4k
1
vote
1
answer
110
views
Arrays, Pointers and Memory addresses instances confusion in C++
I'm learning and playing a bit with pointers and memory addresses.
The thing is that I've tried doing some moves with instances inside arrays and getting their memory address, and I can't figure out ...
- 23
-1
votes
0
answers
34
views
invalid covariant return type for [duplicate]
Consider the following example, which is some part of the bigger codebase, in the getInstance() if I dont return a pointer to the derived class, i.e., just void or int or a different type, the ...
- 7,670