Recent questions tagged C++

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c++ - changing the directory from inside a c program under windows using system command

I have a problem where I have to run a command prompt command from inside a C program. Here is what I did ... advise on how may I do 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++ - Conditional compilation based on template values?

the question posed in: Type condition in template is very similar, yet the original question wasn't quite ... based on template values. 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++ - Unable to print the value of nullptr on screen

I was reading about nullptr and doing workout on g++ and also on VS2010. When I did #include <iostream> ... the value of nullptr on screen? 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++ - C++11 cross compiler/standard library random distribution reproducibility

While the random engines are required to give the same sequence of numbers on each compiler. At least some ... environment you are given? 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++ - Inheriting constructors and brace-or-equal initializers

I don't understand why you can't compile a class which has both a member (not default constructible) with a ... behave) just fine on MSVC14. 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 difference between if (NULL == pointer) vs if (pointer == NULL)?

What is the difference between using: if (NULL == pointer) and using: if (pointer == NULL) My professor ... see the 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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c++ - Is static init thread-safe with VC2010?

I've been looking all around SO and MSDN for an answer to this question, but cannot seem to find a ... safeness of local static variable init. 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++ - Most efficient way to check if all __m128i components are 0 [using <= SSE4.1 intrinsics]

I am using SSE intrinsics to determine if a rectangle (defined by four int32 values) has changed: __m128i oldRect ... was posted and answered). 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 for the executable to ask for Administrator rights? (Windows 7)

I am developing a partition disk program, and for me to read the \\.\PhysicalDrive0 I need admin rights. ... execute arbitrary commands as adm. 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 do I get crtdbg.h file?

I am using MinGW GCC + Eclipse on Windows, and I have run into this error: C:Program FilesITG Derivatives ... it and solve this problem? 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++ global object

I wanna create a global object in cpp program, how do I do that? Is this right? in "global_obj.h" #include " ... in "main.cpp" extern Class obj; 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 detect negative numbers as parsing errors when reading unsigned integers?

I want to read unsigned integers in base-10 (decimal) representation from a C++ iostream with at least rudimentary ... 0") as conversion errors? 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++ - vector memory allocation strategy

i wrote a little piece of code to determine, how memory allocating in a vector is done. #include <iostream> ... for large numbers of elements? 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 does std::vector work with incomplete types in class definitions?

The following question came up: The c++ standard seems to say, that std::vector requires a complete type to ... understand the c++11 version. 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++ - Strange behavior with constexpr static member variable

This is a follow up question to Undefined reference to static constexpr char[][]. The following program builds ... array causes a linker error. See Question&Answers more detail:os...

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

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295 views

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c++ - Does std::bind work with move-only types in general, and std::unique_ptr in particular?

I'm trying to use boost::asio and run into a bit of a quagmire. I'm trying to compile the following code: std:: ... :tuple(const std::tuple< <template-parameter-1-1> >&) [...

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

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c++ - Why does MSVC pick a long long as the type for -2147483648?

My snippet: auto i = -2147483648; int j = 3; std::swap(i, j); // Compile error about mismatched types ... compiler is MSVC, target is 64 bits. See Question&Answers more detail:os...

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

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357 views

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c++ - splice() on std::list and iterator invalidation

The 3-argument form of list::splice() moves a single element from one list to the other. SGI's ... iterator debugging is turned off). 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 check deallocation of memory

How to check if memory to which pointer p points has been succesfully deallocated? 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++ - Displacement Map Filter in OpenCV

I'm curious to know how one can implement the effect demonstrated here using OpenCV. I think it's some sort of ... would I go about doing 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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102 views

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c++ - How to Run Only One Instance of Application

I have a application which uses socket connection to send and receive data from another application. While creating ... application to the Top. See Question&Answers more detail:os...

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

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393 views

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c++ - Unable to find Eigen3 with CMake

I am kind of desperate: For my studies I need to work with Eigen and CMake. I'm able to use Eigen if I ... 's going wrong? Kind regards, Julien 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++ - Passing NON-POD type to Variadic function is undefined behavior?

In this document, the author said Only a POD-type can be an argument for the ellipsis "..." while std:: ... rightly and this is a standard. 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 are these seemingly-useless callq instructions in my x86 object files for?

I have some template-heavy C++ code that I want to ensure the compiler optimizes as much as possible due to ... code generation using clang 3.7. 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 set given channel of a cv::Mat to a given value efficiently without changing other channels?

How to set given channel of a cv::Mat to a given value efficiently without changing other channels? For ... no longer have this property. 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++ - Appending std::vector to itself, undefined behavior?

This question made me uncertain about appending a vector to itself. So the question is: Following lines of ... ); Or implementation depending? See Question&Answers more detail:os...

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

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242 views

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c++ - Qt equivalent of PathAppend?

PathAppend is a useful winapi function that lets you append one path to another while taking care of any trailing ... that does a similar thing? 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++ - GCC std::thread not found in namespace std

I am using GCC 4.5.0 with the Eclipse IDE (if that matters) on Windows via MinGW. I'm using the -std=c ... find the header, but still no cigar. See Question&Answers more detail:os...

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

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