Recent questions tagged C++

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c++ - How to merge two BST's efficiently?

How to merge two binary search trees maintaining the property of BST? If we decide to take each element from a tree and ... O(n1 * log(n2))? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - QObject: Cannot create children for a parent that is in a different thread

I am using Qt 4.6.0 (32 bit) under Windows 7 Ultimate. Consider the following QThread: Interface class ResultThread ... mean? How to solve it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Template Metaprogramming - Difference Between Using Enum Hack and Static Const

I'm wondering what the difference is between using a static const and an enum hack when using template metaprogramming ... but why use it now? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to convert a command-line argument to int?

I need to get an argument and convert it to an int. Here is my code so far: #include <iostream> using namespace ... Convert it to an int here } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - #include errors detected in vscode

I am using Visual Studio Code in my C++ project. I installed Microsoft C/C++ Extension for VS Code. I got ... be provided by the Tag Parser. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Get the status of a std::future

Is it possible to check if a std::future has finished or not? As far as I can tell the only way to do it ... not, but is there a better way? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - When Does Move Constructor get called?

I'm confused about when a move constructor gets called vs a copy constructor. I've read the following sources: ... to ask many more questions. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - What does an ampersand after this assignment operator mean?

I was reading through this nice answer regarding the "Rule-of-five" and I've noticed something that I don't ... have a reference for this? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Use-cases of pure virtual functions with body?

I recently came to know that in C++ pure virtual functions can optionally have a body. What are the real-world use cases for such functions? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is make_shared really more efficient than new?

I was experimenting with shared_ptr and make_shared from C++11 and programmed a little toy example to see what ... the outlined copy overhead? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - What is the purpose of __cxa_pure_virtual?

Whilst compiling with avr-gcc I have encountered linker errors such as the following: undefined reference to ` ... as an infinite loop? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - MinGW .exe requires a few gcc dll's regardless of the code?

When compiling with MinGW, I have to copy over certain dll files from the MinGW bin directory before the exe will run ... << endl; return 0; } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How does this program work?

#include <stdio.h> int main() { float a = 1234.5f; printf("%d ", a); return 0; } It displays a ... statement to study the behaviour of printf. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Can't Overload operator<< as member function

I am trying to overload operator<< as a member function. It works if simply do this: friend ostream& operator<< ... function, but not sure why? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is destructor called if SIGINT or SIGSTP issued?

I have a class with a user-defined destructor. If the class was instantiated initially, and then SIGINT is issued (using ... (CTRL + Z in unix)? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why use array size 1 instead of pointer?

In one C++ open source project, I see this. struct SomeClass { ... size_t data_length; char data[1]; ... ... see NULL. Is there anything else? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - enum vs constexpr for actual static constants inside classes

Let me start by stating my intent. In the olden (C++) days, we would have code like: class C { ... the error: constexpr int C::SOME_VALUE; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why use !! when converting int to bool?

What can be a reason for converting an integer to a boolean in this way? bool booleanValue = !! ... other difference between the two? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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311 views

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c++ - How to sort an STL vector?

I would like to sort a vector vector<myClass> object; Where myclass contains many int variables. How can ... specific data variable of myClass. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to define several include path in Makefile

New to C++; Basic understanding of includes, libraries and the compile process. Did a few simple makefiles yet. My ... rm -r test.o make.out See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Explicit Return Type of Lambda

When I try and compile this code (VS2010) I am getting the following error: error C3499: a lambda that has been ... expression, flags); })); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Do c++11 lambdas capture variables they don't use?

When I use [=] to indicate that I would like all local variables to be captured by value in a lambda, will that ... don't use it in the lambda? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Some clarification needed about synchronous versus asynchronous asio operations

As far as I know, the main difference between synchronous and asynchronous operations (i.e. write() or read( ... idea use asynchronous in this. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Does the restrict keyword provide significant benefits in gcc/g++?

Has anyone ever seen any numbers/analysis on whether or not use of the C/C++ restrict keyword in gcc/g ... which strongly recommends its usage. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Handling header files dependencies with cmake

I am using CMake on a small C++ project and so far it works great... with one twist :x When I change ... the includes were referenced at all :x See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Can the C preprocessor be used to tell if a file exists?

I have a very large codebase (read: thousands of modules) that has code shared across numerous projects that all ... way instead. Any ideas? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Implicit VS Explicit Conversion

The C++ Standard Library by Nicolai M. Josuttis states: There is a minor difference between X x; Y y(x) // ... explicit" key word, if at all? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - get absolute value without using abs function nor if statement

I was thinking how to get the absolute value of an integer without using if statement nor abs(). At first ... other alternatives ways to do it. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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