Recent questions tagged C++

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c++ - Accessing the [] operator from a pointer

If I define a pointer to an object that defines the [] operator, is there a direct way to access this operator ... alternative to (*VecPtr)[]. 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++ - Check if a type is from a particular namespace

I would like to check if a type is from a particular namespace. Here is what I came up with: #include < ... type is from the expected namespace. 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 SFINAE for template class specialisation

suppose I have these declarations template<typename T> class User; template<typename T> class Data; and want ... in partial specialization.) 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++ - Undefined Symbols for architecture x86_64: Compiling problems

So I am trying to start an assignment, my professor gives us a Main.cpp, Main.h, Scanner.cpp, ... solutions would be greatly appreciated. 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++ - libgmp-10.dll is missing

I recently installed MinGW on my 64-bit Windows 7 computer and when I attempt to compile the most basic of c ... is missing from your computer." 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 use the "this" pointer in an initialization list?

I have two classes with a parent-child relationship (the Parent class "has-a" Child class), and the Child class ... {}; private: Child child; } 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++ - Find mapped value of map

Is there a way in C++ to search for the mapped value (instead of the key) of a map, and then return the ... the values and keys are all unique). 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 a way to do a #define inside of another #define?

I know that I am trying to shoot myself in the leg ;) However, it will allow me to make the rest (big amount) ... ; // this will use new macro } 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 force GCC to assume that a floating-point expression is non-negative?

There are cases where you know that a certain floating-point expression will always be non-negative. For example, ... -specific, etc. solutions. 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 initialize and print a std::wstring?

I had the code: std::string st = "SomeText"; ... std::cout << st; and that worked fine. But now my team ... "SomeText". What am I doing 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++ - getchar_unlocked( ) VS scanf() VS cin

What is the difference among these three input functions in programming language. Do they input in different ... <cstdlib> #include<cassert> 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 create class objects dynamically?

Let's say I have a class box, and a user can create boxes. How to do it? I understand I create ... dynamically, depending on the user input? 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++ - Detect operator support with decltype/SFINAE

A (somewhat) outdated article explores ways to use decltype along with SFINAE to detect if a type ... type supports certain expressions? 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++ Implementing Timed Callback function

I want to implement some system in c++ so that I can call a function and ask for another function to be ... would a feature like this work? 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++ - Undefined symbols for architecture x86_64 - Mavericks (Yosemite, El Capitan...)

EDIT : If you fall on this post, you may want to jump directly to the answer I sent a post ... error Undefined symbols for architecture x86_64. 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 the size of a class depends on the order of the member declaration? and How?

Someone explain me how does the order of the member declaration inside a class determines the size of that class. ... class is 12 bytes. How? 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++ - Compile-time map and inverse map values

Can someone recommend a more elegant way to achieve these compile-time constants? template <int> struct Map; template < ... forget to do even). 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 assignment operator '=' atomic?

I'm implementing Inter-Thread Communication using global variable. //global var volatile bool is_true = true; ... use assignment operation 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++ - error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup, but this time it's NOT a Windows/Console problem!

So, the infamous error is back. The project is complaining that it can't find the main() method (that's what ... ); glutMainLoop(); return 0; } 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 does the "L" mean at the end of an integer literal?

I have this constant: #define MAX_DATE 2958465L What does the L mean in this sense? 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 print UTF-8 strings to std::cout on Windows?

I'm writing a cross-platform application in C++. All strings are UTF-8-encoded internally. Consider the ... C++ documentation on asserts. See Question&Answers more detail:os...

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

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203 views

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c++ - How to add element by element of two STL vectors?

The question is quite dumb, but I need to do it in a very efficient way - it will be performed over ... . How should result be initialized? See Question&Answers more detail:os...

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

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254 views

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c++ - Is it safe to realloc memory allocated with new?

From what is written here, new allocates in free store while malloc uses heap and the two terms often mean the ... the same area if possible. See Question&Answers more detail:os...

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

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162 views

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c++ - Why is there no 2-byte float and does an implementation already exist?

Assuming I am really pressed for memory and want a smaller range (similar to short vs int). Shader languages already ... is no 2-byte float. 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++ - templated typedef?

I'm using libgc, a garbage collector for C and C++. To make STL containers garbage collectible one must use the ... <int>> verbose = fib; See Question&Answers more detail:os...

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

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245 views

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c++ - Pack expansion for alias template

It seems that a pack argument can be expanded only in the place of a pack parameter of an alias template. This is ... template x_t<Args...> v2; See Question&Answers more detail:os...

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

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213 views

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c++ - How much overhead is there when creating a thread?

I just reviewed some really terrible code - code that sends messages on a serial port by creating a new ... when actually creating a thread? See Question&Answers more detail:os...

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

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282 views

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c++ - Waiting for multiple futures?

I'd like to run tasks (worker threads) of the same type, but not more than a certain number of ... better solution with async/future possible? See Question&Answers more detail:os...

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

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