Recent questions tagged c++

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c++ - Why is returning a reference to a function local value not a compile error?

The following code invokes undefined behaviour. int& foo() { int bar = 1234; return bar; } g++ issues a ... the spec not prohibit such 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++ - How can I make QtCreator break on exceptions?

I am Debugging some BOOST unit tests in QtCreator and it sadly happened that they crash with an exception. How ... about both of these IDEs. 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 both runtime-sized arrays and std::dynarray in C++14?

Draft C++14 includes both runtime-sized arrays and the std::dynarray container. From what I can tell, the only real ... or anything in C++11. 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++ - Precision of multiplication by 1.0 and int to float conversion

Is it safe to assume that the condition (int)(i * 1.0f) == i is true for any integer i? 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 memory layout of vector of arrays?

can anybody explaine the memory layout of std::vector<std::array<int, 5>> vec(2) does it provide contiguous ... same for the vector of arrays? 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 install (v142) Build tools in Visual studio

As I am trying to build something in visual studio then visual studio show me some warning and then If i ... then selecting "Retarget solution". 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 get a pointer to one subobject via a pointer to a different, unreleated subobject?

Look at this simple code: struct Point { int x; int y; }; void something(int *); int main() { Point p{1, 2} ... &p.y);, and return p.x; instead? See Question&Answers more detail:os...

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

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359 views

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c++ - Getting filename (or path) from fstream

Can I get a file name or its path from a fstream object? I looked through the methods of fstream and didn't find anything close to it. 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++ - Qt 5 : update QProgressBar during QThread work via signal

I'm trying to update a QProgressDialog (owned by a QMainWindow class) along the execution of a QThread who process ... what I'm doing wrong ? 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++ - enable_if iterator as a default template parameter?

I have a constructor like that : class MyClass { template<class TI> MyClass(TI first, TI last); }; template< ... ) ? Thank you very much. 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 get the android <shared-storage> path from Qt?

I've had to upload a separate expansion file with my app (developed in Qt) in Google Play console. It's a ... to get the shared-storage 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++ - Converting integer to Roman Numeral

I have a test due in about four hours and one of the questions asks us to convert a user-inputed integer up to ... ; return 0; } enter code here See Question&Answers more detail:os...

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

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262 views

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c++ - opencv estimateRigidTransform: How to get global scale?

I'm using openCV's estimateRigidTransform to stabilize a series of video frames, which works very well. The function ... get this value from M? See Question&Answers more detail:os...

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

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218 views

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c++ - Specialized QValidator and QML UI changes

I'm learning Qt 5.5 and QML. The framework is powerful, and there are sometimes many ways to do one ... . Complete source code available here. 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++ - Lib svm, how to convert MyModel.mat to MyModel.model

I have a .mat file which could be easily read by matlab, but I need to convert it a C++ readable . ... (by hands, or maybe programmatically)? 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++ - [[carries_dependency]] what it means and how to implement

I was reading about [[carries_dependency]] in this SO post. But what I could not understand is the ... state about carrying the dependency? See Question&Answers more detail:os...

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

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308 views

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c++ - dlclose() doesn't work with factory function & complex static in function?

I'm making a simple plugin framework in which I'd like to be able to dlopen() a shared library (i.e ... an factorified class's member function? See Question&Answers more detail:os...

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

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446 views

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c++ - Force close file by its path on Windows

I'm writing a temporary file manager for other developers. I want to remove files even our console ... opened by current application? 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++ - DirectX Screen Capture and Output as Video

I am doing desktop screen capture and wanted the output to be a video file. Currently I have codes getting from here ... (img); } return hr; } 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++ - Custom type in QVariant converts to empty string

I'm writing a lexical scanner that generates a stream of tokens from some input. Those tokens have a type and a ... if that is suggested). ? See Question&Answers more detail:os...

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

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367 views

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c++ - Direct access to harddrive?

I was wondering how hard disk access works. Ex, how could I view/modify sectors? Im targeting Windows if that helps. Thanks See Question&Answers more detail:os...

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

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323 views

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c++ - Is there any qt signal for sql database change?

I wrote a C++ program using Qt. some variables inside my algorithm are changed outside of my program and in a web page ... .. this goes on ... } See Question&Answers more detail:os...

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

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312 views

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c++ - Find largest and smallest number in an array

Consider: #include <iostream> // Include header file using namespace std; int main () //start of main ... them separately. Any suggestions? See Question&Answers more detail:os...

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

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205 views

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c++ - make include directive and dependency generation with -MM

I want a build rule to be triggered by an include directive if the target of the include is out of date or ... ${program_SRCS:.c=.d} endif 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 operator = doesn't get inherited from a template class

I have following template code: class ClassName{}; template <class T> class TemplatePtr { public: void operator= ... in the template base class? See Question&Answers more detail:os...

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

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396 views

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c++ - Number of Increasing Subsequences of length k

I am trying to understand the algorithm that gives me the number of increasing subsequences of length K in ... out understand this algorithm. See Question&Answers more detail:os...

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

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490 views

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c++ - wostream fails to output wstring

I am using Visual Studio C++ 2008 (Express). When I run the below code, the wostream (both std::wcout, and ... .flush(); myFile.close(); } See Question&Answers more detail:os...

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

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741 views

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c++ - OpenCV - Fit a curve to a set of points

This follows my post here: OpenCV - Remove "white" artifacts from image and fit a curve I removed the extraneous ... and could not find a way. See Question&Answers more detail:os...

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

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