Recent questions tagged C++

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c++ - 3D Scene Panning in perspective projection (OpenGL)

I have designed a C++ class that abstracts the user from trackball rotation, zooming and panning. I have ... implementation detail for OpenGL. 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++ - QT example executables won't run, missing QT5Cored.dll

QT5Cored.dll is on my system @: C:Qt5.4mingw491_32in folder The Analogclock example and other projects will run ... added to exe directory. 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++ - Optimization due to constructor initializer list

Constructors should initialize all its member objects through initializer list if possible. It is more efficient than ... help of an example? 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++ - Unresolved external symbols in beginners CUDA program

I create a new Win32 Console App as an empty project I am running Windows 7 64bit with Visual Studio 2008 C++. ... simple here, but what is 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++ - Is it impossible to use an STL map together with a struct as key?

I have the following code: struct Node { int a; int b; }; Node node; node.a = 2; node.b = 3; map<int, ... an int, I got a compile error. 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++ - int8_t vs char ; Which is the best one?

I know both are different types (signed char and char), however my company coding guidelines specifies to use ... best practices to use int8_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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c++ - How to order types at compile-time?

Consider the following program: #include <tuple> #include <vector> #include <iostream> #include <type_traits ... metaprogramming techniques? 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 hide the exported symbols name within a shared library

For VC, I can write a DEF file and use the 'NONAME' directive to leaving only the ordinal number in dll's ... way to solve my problem :-D 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 unordered_set that has elements that are vector of pair<int,int>

I wanted to have something like unordered_set<vector<pair<int,int>>> us; but even without pair: #include <vector> ... error: invalid use of incomplete type struct std::hash<st...

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

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c++ - Selected Rows in QTableView, copy to QClipboard

I have a SQLite-Database and I did it into a QSqlTableModel. To show the Database, I put that Model into a ... to put this into the Clipboard. 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++ - Casting negative integer to larger unsigned integer

I've encountered code that performs the following conversion: static_cast<unsigned long>(-1) As far as I can ... static_cast<unsigned long>(-1) 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++ - gcc 4.3.3 compiler options enabled by default

I have moved from gcc version 4.0.3 to 4.3.3 and realized that -mfpmath was set to sse by ... has effect on performance and functionality.) 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++ - Copy constructor with pointers

I have recently discovered that when I have pointers within a class, I need to specify a Copy constructor. To learn ... constructor in 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++ - Using static variable along with templates

I have a template class defined in a header file like this. Here I have defined a static variable as ... static variables along with templates? 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 NULL/0 an illegal memory location for an object?

I understand the purpose of the NULL constant in C/C++, and I understand that it needs to be represented ... of memory due to this reservation? 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 create executable file for a Qt Application?

I've been searching on the internet for some useful and clear information about this, it's annoying that such a ... give me some light here. 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++ - From thrust::device_vector to raw pointer and back?

I understand how to go from a vector to a raw pointer but im skipping a beat on how to go backwards. // ... explain/point me to an example? 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 display pixels on screen directly from a raw array of RGB values faster than SetPixel()?

I enjoy making "animations" in c++ such as a MandelBrot Set zoomer, Game of Life simulator etc. by setting pixels ... Code::Blocks as my IDE. 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++ - char vs wchar_t when to use which data type

I want to understand the difference between char and wchar_t ? I understand that wchar_t uses more bytes but can ... would use char vs wchar_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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c++ - Using clang++, -fvisibility=hidden, and typeinfo, and type-erasure

This is a scaled down version of a problem I am facing with clang++ on Mac OS X. This was seriously ... to expose publicly the wrapped types. 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 do you enable C++11 syntax in Eclipse Neon?

I am developing C+11 code in Eclipse Neon and noticed today that the range based for loop introduced in C+11 ... using a separate build system) 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's the relation of "win32 project" name in visual studio to x86 or x64 platform

I'm using Visual Studio for c++ programming, and after working and writing programs in x86 environment (32bit Mode) ... why it is called win32? 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++ - Pointers to elements of STL containers

Given an STL container (you may also take boost::unordered_map and boost::multi_index_container into account) that is non- ... std::list<ABC*>. 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++ - Aligned and unaligned memory accesses?

What is the difference between aligned and unaligned memory access? I work on an TMS320C64x DSP, and I want to use ... When should I use which? 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++ - Workaround for blocking async?

The async call below is blocking because the destructor of the returned future is blocking: void foo() {} ... recommend a different 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++ - CMake with Google Protocol Buffers

I'm trying to use cmake to build my little project using protocol buffers. There's a root directory with a number of ... main() { 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++ - Convert "this" pointer to string

In a system where registered objects must have unique names, I want to use/include the object's this pointer in the ... name = ???(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++ - FMA3 in GCC: how to enable

I have a i5-4250U which has AVX2 and FMA3. I am testing some dense matrix multiplication code in GCC 4.8.1 ... quite a bit faster than Eigen). See Question&Answers more detail:os...

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

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