Recent questions tagged C++

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c++ - No matching function for call to Class Constructor

I am practicing my OOP and I have the following classes: Point and Circle. Specifically, Circle has a ... parameter in my Circle constructor? 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++ - Changing a C# delegate's calling convention to CDECL

I have had this problem with C# when I was using DotNet1.1 The problem is this. I have an unmanaged dll, which ... my pain in the buttocks :) 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 count cameras in OpenCV 2.3?

I want to get the number of available cameras. I tried to count cameras like this: for(int device = 0; ... using Windows 7 and USB cameras. 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++ - Algorithm to add or subtract days from a date?

I'm trying to write a Date class in an attempt to learn C++. I'm trying to find an algorithm to add ... know of an algorithm which does 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++ - Using char16_t and char32_t in I/O

C++11 introduces char16_t and char32_t to facilitate working with UTF-16- and UTF-32-encoded text strings. ... complement the wchar_t support? 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 can't C++11 move a noncopyable functor to a std::function?

//--------------------------------------------------------------------------- ... I do that it actually works to give it to a std::function. 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 a variable be declared both static and extern?

Why the following doesn't compile? ... extern int i; static int i; ... but if you reverse the order, it compiles ... ... What is going on 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++ - How to handle a transitive dependency conflict using Git submodules and CMake?

We have a number of Git repositories, some containing our own code and some containing slightly modified third- ... remains unanswered anyway.) 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 pointer to int convert to void* but pointer to function convert to bool?

The C++ Draft Standard (N3337) has the following about conversion of pointers: 4.10 Pointer conversions 2 An rvalue ... foo(bool) In foo(void*) 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++ - Hash function for floats

I'm currently implementing a hash table in C++ and I'm trying to make a hash function for floats... ... understand why (besides the speed) 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 Microsoft Visual Studio equivalent to GCC ld option --whole-archive

When linking a static library against an executable, unreferenced symbols are normally discarded. In my case some ... used more than once. 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++ - Will specialization of function templates in std for program-defined types no longer be allowed in C++20?

Quote from cppreference.com: Adding template specializations It is allowed to add template specializations for any ... hopefully will). 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 directly bind a member function to an std::function in Visual Studio 11?

I can easily bind member functions to a std::function by wrapping them with a lambda expression with capture clause. class ... (int)' on a 'int' 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 ascii value of EOF in c.?

Any one knows what is the ASCII value of i. I try printf("%d",EOF); but its print -1 and also try printf ... . so anyone know which key for EOF. 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++ - Boost linker error: Unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::get_system_category(void)"

I'm just getting started with Boost for the first time, details: I'm using Visual Studio 2008 SP1 I'm ... infact linking in the system lib. 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++ - Pointer interconvertibility vs having the same address

The working draft of the standard N4659 says: [basic.compound] If two objects are pointer-interconvertible, then they ... i2 would result in UB. 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++ - 'was not declared in this scope' error

So I was writing this simple program to calculate the day of any date using the Gaussian algorithm found here. ... please tell me whats wrong. 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 std::fstream failure error messages and/or exceptions

I'm using fstream. Is there any way to get the failure message/exception? For example if I'm unable to open the file? 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 safe to memset bool to 0?

Suppose I have some legacy code which cannot be changed unless a bug is discovered, and it contains this code: bool ... do I to request a fix? 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 tell reliably if a boost thread has exited its run method?

I assumed joinable would indicate this, however, it does not seem to be the case. In a worker class, I ... meaning of boost thread::joinable? 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++ - Print address of virtual member function

I am trying to print the address of a virtual member function. If I know which class implements the function I ... in the vtable at runtime? 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 operator"" with double parameter

Consider: struct str {}; str operator"" _X(long double d) { return str(); } This compiles fine with g++ 4. ... ? Can you think of a workaround ? 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 the _chkstk() function?

I recently used the /FAsu Visual C++ compiler option to output the source + assembly of a particularly long ... function? What does it do? 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 there an automatic noexcept specifier?

I've heard that noexcept keyword is more like 'it should never throw an exception' rather than 'it ... to simplify the noexcept expression? 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 a declaration like int (x); or int (x) = 10;

If you look at the grammar for *declarator*s in §8/4 you'll notice that a noptr-declarator can be ... is not involved in the declaration? 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++ - narrowing conversion from unsigned to double

static_assert(sizeof(unsigned) == 4, ":("); static_assert(sizeof(double) == 8 ,":("); unsigned u ... perfectly representable as a double? 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 recursively create a folder in Win32?

I'm trying to create a function that takes the name of a directory (C:fooar, or ..fooar..az, or \someserverfooar) ... way to do this in C++? 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 generate a newline in a cpp macro?

How do I write a cpp macro which expands to include newlines? See Question&Answers more detail:os...

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

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