Recent questions tagged C++

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c++ - What's the purpose of having a separate "operator new[]"?

Looks like operator new and operator new[] have exactly the same signature: void* operator new( size_t size ) ... and exactly the same behavior? 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++ - Where is <inttypes.h> in Visual Studio 2005?

I'd like to use the C99 header file inttypes.h in a Visual Studio project (I'd like to printf 64 bit ... of VS2005? Are there any alternatives? 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++ - Has "In class member initialization" feature made into C++11?

In class initialization feature, which allows to initialize normal members inside the class itself, struct A { int a = ... doesn't support 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++ - Where does Visual Studio search for txt files when conducting file management operations?

I know this is a noob question, but I've worked with Python before and when you wanted to simply access a .txt ... file.close(); return 0; } 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++ - Certain errors in uninstantiated template not reported by g++

Consider this example: class A { void foo(); public: void bar(); }; template <class> class B { B() { A ... time. Are there nuances I don't see? 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++ - Obtaining item index in ranged based for on vector

The C++11 introduced ranged-based for loop that is internally implemented using (const) iterators so this: std ... probably in the standard) 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++ - Read uint8_t from std::stringstream as a numeric type

My understanding is that reading a uint8_t from a stringstream is a problem because the stringstream will interpret the uint8_t ... // TODO... } 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++ - Can template parameter deduction be used in class data members?

C++17 introduces template argument deduction. With gcc-7.2, I can use it easily in a function: int test ... functions being passed and stored). 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++ - changing const value in C

I find that in the following code snippet const int i = 2; const int* ptr1= &i; int* ptr2 = (int ... in which this could become helpful? 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++ - C++11 Exception's destructor allows to throw now?

any idea why virtual ~exception() throw() is in C++98, but virtual ~exception() is in C++11? What's the ... const char* what() const 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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633 views

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c++ - Backslash newline at end of file warning

With this code: #include <iostream> int main(int argc, char *argv[]) { return 0; } /** run2: A macro to ... idea how to make it go away? David 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 RVO work on object members?

Consider the following: struct A { /* ... */ }; A foo() { auto p = std::make_pair(A{}, 2); // ... ... Will p.first be copied, moved or RVO-ed? 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 purpose of the const overloads of std::begin and std::end?

For std::begin, we have two overloads for containers: template< class C > auto begin( C& c ) -> decltype(c ... is redundant. What am I missing? 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++ - Shouldn't decltype Trigger Compilation of its Argument?

So I'm perplexed as to how this works. Given: template <typename T> int foo(T t) { t.foo(); } It ... request a quote from the C++ Standard. 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 purpose of std::forward()'s rvalue reference overload?

I'm experimenting with Perfect Forwarding and I found that std::forward() needs two overloads: Overload nr. 1: ... used (and is needed)? See Question&Answers more detail:os...

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

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510 views

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c++ - Mixing constexpr declarations and const definitions

I came across the following situation: struct Foo { static constexpr char s[] = "Hello world"; }; const char Foo: ... data member as a const T? See Question&Answers more detail:os...

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

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140 views

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c++ - Size of struct with a single element

Given struct S { SomeType single_element_in_the_struct; }; Is it always true that sizeof(struct S) == ... may be implementation dependent? See Question&Answers more detail:os...

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

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178 views

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c++ - Why does a recursed return call break out of stack without an explicit return statement?

I was shown a sample program to demonstrate recursion which looks like it should not work but does. The logic is pretty clear ... /2) << " "; } 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 use namespace across several files

I notice that C++'s std namespace is spread across several files (like in vector, string, iostream, etc.). ... ; to use the two classes? 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 wchar_t just a typedef of unsigned short?

for example, does: wchar_t x; translate to: unsigned short x; See Question&Answers more detail:os...

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

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337 views

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c++ - Evaluation order of function arguments and default arguments

I recently ran across the following situation: #include <iostream> int *p = 0; int f() { p = new ... the evaluation order of function arguments? See Question&Answers more detail:os...

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

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298 views

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c++ - g++ won't allow generalized capture of const object by reference in lambda?

This is rejected by g++ (4.9.3 and 5.2.0), but is accepted by clang 3.5.0: int main() { const int ... strange constraint, perhaps a bug in g++? See Question&Answers more detail:os...

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

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314 views

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c++ - Lambda capturing constexpr object

GCC 4.7.2 compiles this: constexpr int i = 5; []{ std::integral_constant< int, i >(); }; // ... in the enclosing scope or a reference? 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::array< T, 0 > not empty?

Given any std::array< T, 0 >, why is it not empty? I mean "empty" as in: std::is_empty< std:: ... intentional or an oversight in the standard? See Question&Answers more detail:os...

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

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281 views

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c++ - Is casting of infinity to integer undefined?

Is the casting of infinity (represented by float) to an integer an undefined behavior? The standard says ... information about casting infinity. See Question&Answers more detail:os...

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

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210 views

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c++ - What header should I include for memcpy and realloc?

I am porting a project to the iPhone and it uses realloc and memcpy which are not found. What is the header ... Thanks in advance 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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324 views

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c++ - Optimizing subset sum implementation

I'm working on a solution to a variant of the subset sum problem, using the below code. The problem entails ... code added by popular demand. See Question&Answers more detail:os...

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

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519 views

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c++ - Undefined Reference to class static member in static member

I am creating a linked list with self referential class in C++ and I want to have a static pointer of ... cube.exe] Error 1 Execution terminated See Question&Answers more detail:os...

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

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