Recent questions tagged C++

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c++ - Set default alignment for cells in QTableWidget

I know you can set the alignment for each item using: TableWidget->item(0,0)->setTextAlignment(Qt::AlignLeft); ... new item. Is it possible? 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 can't I move the std::unique_ptr inside lambda in C++14?

I want to pass a raw pointer inside lambda, but I don't want it to be leaked, if the lambda isn't ... and works as expected by semantics? 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++ - Atomic Reference Counting

I'm trying to understand exactly how thread-safe, atomic reference counting works, for example as with std:: ... this possible without a lock? 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++ - cannot convert from 'std::string' to 'LPSTR'

As I clould not pass LPCSTR from one function to another (Data get changed) I tried passing it as a string. ... LPSTR' How can I resolve this? 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 trait / concept can guarantee memsetting an object is well defined?

Let's say I have defined a zero_initialize() function: template<class T> T zero_initialize() { T result; std:: ... class(std::string)? [closed] 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++ - Autotools check for C++11

I use AX_CXX_COMPILE_STDCXX_0X(can look on autoconf-archive) to check for c++11 capabilities of the compiler. ... autoconf developers, not me. 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++ - parse string to vector of int

I have a string which contains some number of integers which are delimited with spaces. For example string ... Sorry for stupid question. 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++ - Pointer to class member as a template parameter

I want to use a pointer to a class member as a template parameter as in: template <class Class, ... constexpr and returning template 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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c++ - std::is_base_of for template classes

Is there a way to test std::is_base_of<A, B> when A is a template class? template <typename X, typename Y> ... is there another way to do this? 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++ - fstream seekg(), seekp(), and write()

I'm looking for some clarification on how seekg() and seekp() works with respect to when you are writing to a ... seekg() and seekp() functions. See Question&Answers more detail:os...

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

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250 views

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c++ - How are exceptions allocated on the stack caught beyond their scope?

In the following code, the stack-based variable 'ex' is thrown and caught in a function beyond the scope in which ... there as well. Any 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 import C makefile project into eclipse or put in under eclipse

I have standard source code package under Linux which requires to run ./configure make to compile it (and it ... . Probably this was 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++ - C: Initializing struct variables after declaration

I encountered this recently but could not figure out why the language would allow b = c; below and fail b = {3, ... ; // this works 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++ - Using pair<int, int> as key for map

Based on a previous question, I am trying to create a map using a pair of integers as a key i.e. map<pair ... key. Am I doing something 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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223 views

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c++ - Is it a strict aliasing violation to alias a struct as its first member?

Sample code: struct S { int x; }; int func() { S s{2}; return (int &)s; // Equivalent to * ... of the above bullet points is it allowed? 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 a destructor considered a const function?

Consider this class Foo { public: Foo(){} ~Foo(){} void NonConstBar() {} void ConstBar() const {} }; ... on a const pointer a special 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++ - How can I specialize a template member function for std::vector<T>

I need to define a get method in two different ways. One for simple types T. And once for std::vector. ... function for this. Thanks a lot. See Question&Answers more detail:os...

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

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388 views

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c++ - Do uniform values remain in GLSL shader if unbound?

I am writing a program that uses two different shaders for different primitives. My question is: if I bind a program, ... ? element.draw(); } } 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++ - Checking if a file opened successfully with ifstream

I have the following that will open a file for reading. However, I want to check to make sure that the file ... = _file_name; 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++ - Forward declaration as struct vs class

I found a mistake in a C++ forward declaration of a class, which was wrongly declared as struct Book instead of ... under the Microsoft C++ ABI See Question&Answers more detail:os...

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

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381 views

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c++ - Check Windows version

How I can check in C++ if Windows version installed on computer is Windows Vista and higher (Windows 7)? 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++ - Mixing virtual and non-virtual inheritance of a base class

This is the code: struct Biology { Biology() { cout << "Biology CTOR" << endl; } }; struct Human : ... But none seems to satisfy my request. 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++ - Defining own main functions arguments argc and argv

i want to create an object of type QApplication which needs the main functions arguments argc and argv as an input ... ; Thanks for any hint. See Question&Answers more detail:os...

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

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428 views

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c++ - Static constexpr int vs old-fashioned enum: when and why?

This is maybe a basic question, but I cannot see the response by myself right now. Consider the following code: ... is not a viable 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++ - Negative NaN is not a NaN?

While writing some test cases, and some of the tests check for the result of a NaN. I tried using std::isnan ... both equality of NaN and -NaN? See Question&Answers more detail:os...

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

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233 views

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c++ - Which parts of the C++14 Standard Library could be and which parts will be made constexpr?

With the new relaxed C++14 constexpr rules, compile-time programming becomes a lot more expressive. I wonder whether ... reasons not to do so? 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 I pass const& std::string instead of std::string_view?

I understand the motivation for using std::string_view; it can help avoid unecessary allocations in function ... for parameter passing? 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 MinGW very slow?

I'm using the Code::Blocks IDE with GCC/MinGW on Windows, and I'm trying to build a wxWidgets application which ... worked. Why is it so slow? See Question&Answers more detail:os...

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

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