Recent questions tagged C++

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c++ - What is the fastest way to change a key of an element inside std::map

I understand the reasons why one can't just do this (rebalancing and stuff): iterator i = m.find(33); ... the node back into the tree Rebalance 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 copy contents of a directory into build directory after make with CMake?

I've got some config files (xml, ini, ...) in the config directory next to the source files. How can I ... file) each time I make the project? 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 fpermissive flag do?

I'm just wondering what the -fpermissive flag does in the g++ compiler? I am getting: error: taking address of ... to fix that part right now. See Question&Answers more detail:os...

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

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242 views

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c++ - Print a binary tree in a pretty way

Just wondering if I can get some tips on printing a pretty binary tree in the form of: 5 10 11 7 6 3 4 2 Right ... ; case 4: 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++ - Cleaning up an STL list/vector of pointers

What is the shortest chunk of C++ you can come up with to safely clean up a std::vector or std::list ... wrap my pointers with smart pointers. 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++ - Netbeans 7.2 shows "Unable to resolve identifier" , although build is successful

I'm using the Netbeans IDE 7.2 with C/C++ plugin (last version 1.18.1.1) and if I build my project ... this bug and how can I solve it? 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++ - Thread pool using boost asio

I am trying to create a limited thread pool class using boost::asio. But I am stuck at one point can some one ... back to stack? 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++ - Fast fixed point pow, log, exp and sqrt

I've got a fixed point class (10.22) and I have a need of a pow, a sqrt, an exp and a log ... code so I cannot use any assembler optimisations. 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 does weak_ptr work?

I understand how to use weak_ptr and shared_ptr. I understand how shared_ptr works, by counting the number of ... things it uses. Thanks. 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++ - QGraphicsView Zooming in and out under mouse position using mouse wheel

I have an application with a QGraphicsView window in the middle of the screen. I want to be able to zoom ... scale under mouse would be great. 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 I typically/always use std::forward instead of std::move?

I've been watching Scott Meyers' talk on Universal References from the C++ and Beyond 2012 conference, and ... :forward<Widget>(param) } See Question&Answers more detail:os...

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

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236 views

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c++ - Can macros be overloaded by number of arguments?

How does this work? How can a C99/C++11 variadic macro be implemented to expand to different things on the ... many arguments are given to it? See Question&Answers more detail:os...

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

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438 views

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c++ - linux perf: how to interpret and find hotspots

I tried out linux' perf utility today and am having trouble in interpreting its results. I'm used to valgrind's ... apply to all 64bit systems). See Question&Answers more detail:os...

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

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433 views

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c++ - How can I iterate over a packed variadic template argument list?

I'm trying to find a method to iterate over an a pack variadic template argument list. Now as with all ... I'm looking forward to help. See Question&Answers more detail:os...

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

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513 views

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c++ - Can const-correctness improve performance?

I have read numerous times that enforcing const-correctness in your C or C++ code is not only a good ... improving your program's performance? See Question&Answers more detail:os...

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

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224 views

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c++ - CUDA and Classes

I've searched all over for some insight on how exactly to use classes with CUDA, and while there is a general ... I'd love to hear alternatives. 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 use _CRT_SECURE_NO_WARNINGS

I have compile error in my simple MFC window application generated from wizard with several lines of code: ... problems without this definition? See Question&Answers more detail:os...

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

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454 views

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c++ - What's the point of g++ -Wreorder?

The g++ -Wall option includes -Wreorder. What this option does is described below. It is not obvious to me why ... warning is enabled by -Wall. See Question&Answers more detail:os...

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

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392 views

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c++ - Is there a way to find all the functions exposed by a dll

I've been searching for a way to get all the strings that map to function names in a dll. I mean by ... a system call to acquire those names. See Question&Answers more detail:os...

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

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227 views

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c++ - c++11 regex slower than python

hi i would like to understand why the following code which does a split string split using regex #include<regex> ... system 99% cpu 0.109 total See Question&Answers more detail:os...

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

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477 views

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c++ - fatal error LNK1104: cannot open file 'libboost_system-vc110-mt-gd-1_51.lib'

Seem I can't get this to work. I made a simple console application (which depend on websocket++ library) which ... -1_51.lib instead. Any idea? See Question&Answers more detail:os...

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

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221 views

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c++ - How can I output the value of an enum class in C++11

How can I output the value of an enum class in C++11? In C++03 it's like this: #include <iostream> using ... _Tp = A]' compiled at Ideone.com See Question&Answers more detail:os...

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

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544 views

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c++ - Error: invalid operands of types ‘const char [35]’ and ‘const char [2]’ to binary ‘operator+’

At the top of my file I have #define AGE "42" Later in the file I use ID multiple times including some ... that you defined in the 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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860 views

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c++ - How do you convert CString and std::string std::wstring to each other?

CString is quite handy, while std::string is more compatible with STL container. I am using hash_map. However, ... std::string and vice versa? 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 you disable the unused variable warnings coming out of gcc in 3rd party code I do not wish to edit?

I'd like to know what switch you pass to the gcc compiler to turn off unused variable warnings? I'm getting ... the -Wall overrides my goal? See Question&Answers more detail:os...

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

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438 views

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c++ - How can I solve the error LNK2019: unresolved external symbol - function?

I get this error, but I don't know how to fix it. I'm using Visual Studio 2013. I made the solution ... /function.cpp" in file unittest.cpp? See Question&Answers more detail:os...

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

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272 views

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c++ - Template default arguments

If I am allowed to do the following: template <typename T = int> class Foo{ }; Why am I not ... being elusive to my complete understanding. See Question&Answers more detail:os...

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

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549 views

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c++ - Lambda capture as const reference?

Is it possible to capture by const reference in a lambda expression? I want the assignment marked below to ... const reference? (August 2015) See Question&Answers more detail:os...

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

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