Recent questions tagged C++

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c++ - Fastest way to Convert String to Binary?

I want to convert a string, using the string class - to Binary. What is the fast way to do this character by ... { myString = "Hello World"; } 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 can I extend a lexical cast to support enumerated types?

I have the following function that will convert a string into a numeric data type: template <typename T> bool ... for everything else. Thank you 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++ - OpenCV warpperspective

For some reason whenever I use OpenCV's warpPerspective() function, the final warped image does not contain everything ... to fix this? Thanks 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 block running two instances of the same program?

I need to make sure that user can run only one instance of my program at a time. Which means, that I have ... Linux/Unix is a priority for me. 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++ - Stepping into Qt sources in Qt Creator (in Ubuntu Linux)

I'm using Qt Creator in Ubuntu. It's installed from the repositories but as it is now, there is no way to ... debugging. How can I enable that? 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++ - With a private modifier, why can the member in other objects be accessed directly?

I have the following code: class A { private: int x; public: A() { x = 90; } A(A a1, A a2) { a1 ... a1 and a2 can access private data member 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++ - Fastest inline-assembly spinlock

I'm writing a multithreaded application in c++, where performance is critical. I need to use a lot of ... spin_unlock: ;unlocking code. } 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++ - Reading and writing a std::vector into a file correctly

That is the point. How to write and read binary files with std::vector inside them? I was thinking something ... how to perform the operation? 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++ - "Step over" when debugging multithreaded programs in Visual Studio

One thing that annoys me when debugging programs in Visual Studio (2005 in my case) is that when I use "step over" ... to be useful for me :) 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++ - Replace multiple spaces with one space in a string

How would I do something in c++ similar to the following code: //Lang: Java string.replaceAll(" ", " "); ... in a string with a single space. See Question&Answers more detail:os...

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

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300 views

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c++ - How to call an external program with parameters?

I would like to call a windows program within my code with parameters determined within the code itself. I'm not ... ASM, C#, Python, etc). 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++ - Win32: Bring a window to top

I have a Windows program which has two 2 windows in it: hwnd (main interface) hwnd2 (toplevel window, ... PostMessage (rather than SendMessage). 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 are the __cplusplus directive defined in various compilers?

My compiler expands it to 199711L. What does that mean? I read that __cplusplus > 199711L signifies C++11. What ... and what does it signify? 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++ - std::mutex performance compared to win32 CRITICAL_SECTION

how does the performance of std::mutex compared to CRITICAL_SECTION? is it on par? I need lightweight synchronization ... than std::mutex ? 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++ - Making a template parameter a friend?

Example: template<class T> class Base { public: Base(); friend class T; }; Now this doesn't work... ... actually can do something like 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++ - Is it possible to pass derived classes by reference to a function taking base class as a parameter

Say we have an abstract base class IBase with pure virtual methods (an interface). Then we derive CFoo, CFoo2 from ... is: Foo(IBase &input); 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++ - Android ndk std::to_string support

I'm using android NDK r9d and toolchain 4.8 but I'm not able to use std::to_string function, compiler throws this ... -std=c++11 with no luck. See Question&Answers more detail:os...

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

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375 views

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c++ - Does delete work with pointers to base class?

Do you have to pass delete the same pointer that was returned by new, or can you pass it a pointer to one ... to everyone who pointed it 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++ - shared_ptr<> is to weak_ptr<> as unique_ptr<> is to... what?

In C++11, you can use a shared_ptr<> to establish an ownership relation with an object or variable and weak_ptr<> ... available in e.g. Boost? 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++ - Compile c++14-code with g++

I'm using g++ 4.8.4 on Ubuntu 14.04 LTS. When trying to compile with '-std=c++14', I get this ... retrieve the latest version, is that correct? See Question&Answers more detail:os...

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

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552 views

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c++ - strdup or _strdup?

When I use strdup in Microsoft Visual C++, it warns me: warning C4996: 'strdup': The POSIX name for this item ... include <string.h> in my code. 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++ - QTcpSocket: reading and writing

I know some similar questions may have been asked already, but the answers to those I found covered very specific ... tips are welcome. Thanks! See Question&Answers more detail:os...

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

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465 views

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c++ - process video stream from memory buffer

I need to parse a video stream (mpeg ts) from proprietary network protocol (which I already know how to do) ... AVFrames to Mat if needed. 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++ - access private member using template trick

From a blog post Access to private members: Safer nastiness by Johannes Schaub - litb: template<typename Tag, ... 's due to ADL mechanism 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 take screenshot in OpenGL

How to take a screenshot of an OpenGL window in C++ and save it to file. I found the glReadPixels() ... not difficult, write code, please. See Question&Answers more detail:os...

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

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542 views

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c++ - How to simulate a mouse movement

How can I simulate a mouse event causing the pointer to move 500 pixels to the left, then click using C++. How would I do something like 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++ - Difference between A* pA = new A; and A* pA = new A();

in C++, what is the exact difference between both following dynamic object creations : A* pA = new A ... difference about performance... Thanks See Question&Answers more detail:os...

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

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592 views

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c++ - Makefile: How to correctly include header file and its directory?

I have the following makefile: CC=g++ INC_DIR = ../StdCUtil CFLAGS=-c -Wall -I$(INC_DIR) DEPS = split.h ... the makefile? How to correct 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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