Recent questions tagged C++

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c++ - Need clarification on definition of literal type

The book I'm reading frequently mentions that a type has to be literal type to use in certain situations, such ... type and what doesn't. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to generate machine code with llvm

I'm currently working on a compiler project using llvm. I have followed various tutorials to the point where I have ... if that has any impact. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - C++11 lambda returning lambda

this piece of code is not something unknown to JS developers function get_counter() { return ( function() ... .cpp 25 1 Test See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to resolve "pure virtual method called"

I understand why this is happening, but I'm stuck trying to resolve it...here is what my code is ... s collection of QList<ShapeProperties*>. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - What is the difference between std::shared_ptr and std::experimental::atomic_shared_ptr?

I read the following article by Antony Williams and as I understood in addition to the atomic shared count ... lock free stack implementation? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Performances of Structs vs Classes

I wonder if there are performance comparisons of classes and C style structs in C++ with g++ -O3 option. ... for the sake of performance. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Should I always call vector clear() at the end of the function?

I have some simple function that uses vector like this (pseudo code): void someFunc(void) { std::vector<std:: ... or this could be ommited ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - what does (template) rebind<> do?

trying to learn more about how the standard library is actually implemented I'm inspecting all containers in ... necessary at that location? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Call of overloaded function is ambiguous

What does this error message mean? error: call of overloaded setval(int)' is ambiguous huge.cpp:18: note: candidates ... setval(0); return 0; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why Compile to an Object File First?

In the last year I've started programming in Fortran working at a research university. Most of my prior ... is preferred over the other? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to use fstream objects with relative path?

Do I always have to specify absolute path for objects instantiated from std::fstream class? In other words, is ... them such as project path? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is it possible to declare a friend function as static?

Here is some C++ example code that compiles and works fine: class A { public: A() {/* empty */} ... ) friend function that is declared static? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Should templated functions take lambda arguments by value or by rvalue reference?

GCC 4.7 in C++11 mode is letting me define a function taking a lambda two different ways: // by value ... to pass lambdas to the last one? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - intrusive_ptr in c++11

Does C++11 have something equivalent to boost::intrusive_ptr? My problem is that I have a C-style ... something like boost::intrusive_ptr. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to unit test deliberate compilation errors of template code

Please note that this is NOT a duplicate of How write a unit test for verifying compiling error? as I' ... are these issues usually approached? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - What are the breaking changes caused by rewritten comparison operators?

There are some new rules about rewritten comparison operators in C++20, and I'm trying to understand how they ... the meaning of existing code? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is fastcall really faster?

Is the fastcall calling convention really faster than other calling conventions, such as cdecl? Are there any ... by calling convention? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why can I assign a new value to a reference, and how can I make a reference refer to something else?

I have couple of questions related to usage of references in C++. In the code shown below, how does it work ... clear this up, would be useful. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Bad practice to return unique_ptr for raw pointer like ownership semantics?

I've written a static factory method that returns a new Foobar object populated from another data object. I've ... instead of a raw pointer? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Do I need a mutex for reading?

I have a class that has a state (a simple enum) and that is accessed from two threads. For changing ... concurrently written by another thread? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why is inherited member not allowed?

I'm beginner to C++ and I'm doing one of the exercises about abstract class and inheritance. This is my ... no luck. Any help is appreciated. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why not mark everything inline?

First off, I am not looking for a way to force the compiler to inline the implementation of every ... What are the runtime disadvantages? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why does the C preprocessor consider enum values as equal?

Why does the std::cout line in the following code run even though A and B are different? #include <iostream> ... an elegant solution for this? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Do we really need "enum class" in C++11?

When we have, struct E { enum E_ { HELLO }; }; // 'E' is inheritable then why do we need, enum ... (because both have public access specifier) ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why do lots of (old) programs use floor(0.5 + input) instead of round(input)?

The differences reside in the returned value giving inputs around tie-breaking I believe, such as this code: int main ... ? Cheapest on the CPU? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Sublime text 3 - compile program and run in terminal

I am using Ubuntu 12.04, and I was wondering, is it possible to automatically run c++ program from terminal? It ... I am using Sublime text 3. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Interview Question : Trim multiple consecutive spaces from a string

This is an interview question Looking for best optimal solution to trim multiple spaces from a string. This ... solution of the problem. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why aren't template specializations allowed to be in different namespaces?

Please, see what I am trying to do: #include <iostream> namespace first { template <class T> class myclass { ... my_integer Can this be done? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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