Recent questions tagged C++

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c++ - Why does MSVC emit a useless MOVSX before performing this Bit Test?

Compiling the following code in MSVC 2013, 64-bit release build, /O2 optimization: while (*s == ' ' || * ... of interest have values under 32.) 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++ - map, lambda, remove_if

So, i've problem with std::map, lambda and stl algorithm(remove_if). Actually, same code with std::list or std::vector ... + 4.6, -std=c++0x. 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++ - Linker error when compiling boost.asio example

I'm trying to learn a little bit C++ and Boost.Asio. I'm trying to compile the following code example: #include ... status How can I fix 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++ - How does this Array Size Template Work?

I came across this snippet template <typename T, size_t N> char (&ArraySizeHelper(T (&array)[N]))[N]; ... . Any help would be appreciated. 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 find and replace all occurrences of a substring in a string?

I need to search a string and edit the formatting of it. So far I can replace the first occurrence of the ... startPos + myString.length(); } 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++ - Accessing child variables through higher level structures

If I have these structures: typedef struct { int x; } foo; typedef struct { foo f; } bar; Normally you ... figure out how that could be done. 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++ - Forward declare FILE *

How do I forward declare FILE * in C? I normally do this using struct MyType;, but naturally this doesn't ... source file is a bit hackish. 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 a proper way to implement is_swappable to test for the Swappable concept?

I would consider "proper" implementation for is_swappable to be the following: template<class T, class U ... is_swappable without compiler help? 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 output an int in binary?

int x = 5; cout<<(char)x; the code above outputs an int x in raw binary, but only 1 byte. what I need it ... do the trick, how would I do 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++ - Why is the size not a template argument of std::initializer_list?

std::initializer_list is constructed by the compiler from a brace-enclosed init list and the size of this list ... a std::initializer_list). 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++ - are C functions declared in <c____> headers guaranteed to be in the global namespace as well as std?

So this is something that I've always wondered but was never quite sure about. So it is strictly a matter of ... any other scoped they are in). 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++ - Are these null pointers, or are they pointers to address 0?

If I write int zero = 0; void *p1 = (void *)0; void *p2 = (void *)(int)0; void *p3 = (void *)(0 /*no- ... C and C++, what is it in each of them? 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++ - Generate next largest or smallest representable floating point number without bit twiddling

Given an arbitrary finite floating point number, is there a way to determine what the next representable ... represents floating point values? 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++ - CComVariant vs. _variant_t, CComBSTR vs. _bstr_t

I am using ATL (VS2008, so ATL9 IIRC) to create COM objects and have been using the CComVariant class (defined ... should I prefer and why? 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 is std::map's move constructor not noexcept?

As said by cppreference.com, Maps are usually implemented as red-black trees. So moving a std::map is ... constructor not marked as noexcept? 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++ - Returning object from function

I am really confused now on how and which method to use to return object from a function. I want some feedback ... way to handle this 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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c++ - Profiling in Visual Studio 2008 PRO

How do I use the profiler in Visual Studio 2008? I know theres a build option in Config Properties -> Linker ... is the documentation for 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++ - Does std::ofstream truncate or append by default?

If you call the std::ofstream constructor without openmode flags, the default flag is ios_base::out. But does ... it replace the prior contents? 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++ - May STL iterator methods throw an exception

Destructors may not throw exceptions (so stack unwinding can complete during exception handling), and must deallocate ... objects for you. 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++ - Am I right in saying that const_cast followed by modification on a ref-to-const bound to a temporary is okay?

I would like to check my understanding and conclusions on this matter. On IRC, it was asked: Is it ... advisable is another matter entirely!) 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++ - Count of parameters in a parameter pack? Is there a C++0x std lib function for this?

I was just wondering if there was anything in the C++0x std lib already available to count the number of parameters in a ... () : data() { } }; 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 happened to std::assert

This answer and it's multitude of duplicates indicate that I should be using #include <c*> for the C ... oversight, or an actual exception? 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++ - When would you use template explicit instantiation?

I've just been reading about template explicit instantiation: template struct MyStruct<long>; It was described as " ... would it be useful? 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++ - Redirecting function output to /dev/null

I am using a library that is printing a warning message to cout or cerr. I don't want this warning ... result is that nothing is printed. 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 long does thread creation and termination take under Windows?

I've split a complex array processing task into a number of threads to take advantage of multi-core ... after. Any feedback appreciated. See Question&Answers more detail:os...

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

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326 views

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c++ - Why can't operator () of stateless functor be static?

Why is operator () of stateless functor not allowed to be static? Stateless lambda objects are convertible to pointers ... () is not overloaded. See Question&Answers more detail:os...

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

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184 views

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c++ - How to define thread-local local static variables?

How to define local static variables (that keeps its value between function calls) that are not shared among different threads ... in C and C++ 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++ - Locally disable padding

I write a parser for some data structure, after hours of debugging I found out that the problem is Visual Studio ... . Thank you for your help. See Question&Answers more detail:os...

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

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