Recent questions tagged C++

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c++ - Usage of std::swap() inside move assignment should cause endless recursion (and causes), but it is an example from Stroustrup's book

I'm trying to get the deep knowledge about how should I write my copy and move constructors and assignment ... swap() inside move assignment? 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++ - drawing waveform - converting to DB squashes it

I have a wave file, i have a function that retrieves 2 samples per pixel then i draw lines with them. quick ... an average when converted to DB. 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++ - stringstream::str copy lifetime

Something a lot of C++ programmers miss (read: me) when first using stringstreams is the fact that the ... looking for mechanics and rationale. 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++ - Find the reverse of a number (ex : 2500 reverse 0025) without the help of string or character

Is there any technique for finding the reverse when there are zeros at the end. While following the algorithm of ... or Character or array). 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++ - Combining rules at runtime and returning rules

I am trying to write some complex parser made on top of Spirit-X3, so I need to know some things: ? How to ... can't use just a x3::sequence 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++ Segmentation fault when trying to reverse print an array

I have a array consisting of chars like [1,2,3,4,5,.,..] and I have a loop that looks like for ( ... error. Any reason why this can happen? 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 there any way to declare mutual friend functions for two classes

class CDB; class CDM { public: friend CDB& CDB::Add(const CDM&); CDM& Add(const CDB&); }; class CDB { public ... 'CDB'. How to 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++ - Replacing switch statements when interfacing between templated and non-templated code

The X: A common pattern I'm seeing is that the underlying code for a function is templates, but for "reasons" ... similar or have a better way? 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++ - Function with variable parameter size: How to conditionally set some arguments?

To create a boost::process with output redirection, you should do: bp::ipstream out; bp::child c("c++filt", std_out ... should I put 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++ - Ordered sort in STL containers

Sorry if the question title terminology is wrong, but here is what I want to do.I need to sort a vector ... ,id_planet] id_ property is string. 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 start a QThread on a signal?

I want to start a QThread when another one starts, but it doesn't work. main.cpp snippet Worker stat_worker; ... for replying to my post. 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++ - Error while using QTcpSocket

I am creating a (very basic) MJPG server to show webcam data on a browser. I have partly managed to do it ... from one image to the other. 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 DECLARE_DYNAMIC & IMPLEMENT_DYNAMIC nessary for DYNAMIC_DOWNCAST?

I have two classes: /*Switch.h*/ class CSwitch : public CDeviceEntity {} /*EndSystem.h*/ class ... serialization when saving the document. See Question&Answers more detail:os...

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

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700 views

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c++ - Better algorithm for edge filter in video programming

I'm still working on the last program and although I finally found out how to solve the problem (on how ... picture). Thanks in advance. Cheers See Question&Answers more detail:os...

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

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742 views

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c++ - Two questions related to virtual functions

I was reading this articles , was at this heading Inheritance of Base-class vPtrs , but couldn't understand what did ... type is void* . Thanks See Question&Answers more detail:os...

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

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754 views

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c++ - How to change the size of a QComboBox's QScrollBar?

I'm using a QComboBox with some items to the point that, when the widget that shows all available items ... ) Other options are discussed 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++ - passing thrust::device_vector to a function by reference

I'm trying to pass device_vector of structures struct point { unsigned int x; unsigned int y; } to a function in a ... "y" What's wrong with 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++ - Why might HttpOpenRequest fail with error 122?

The following code fRequestHandle = HttpOpenRequestA( fConnectHandle, "POST", url.c_str(), NULL, NULL, NULL, ... which wininet has no limit 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 I compile this on mac by terminal command

I am using xcode to compile my opencv project, and I have some settings as below: HEADER_SEARCH_PATHS = /usr/ ... rather than setting of xcode. 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++ - asio::io_service and thread_group lifecycle issue

Looking at answers like this one, we can do stuff like: boost::asio::io_service ioService; boost::thread_group ... cleaner 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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769 views

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c++ - How to pass structure as pointer in C dll from C#

I am working on simple telephony application where I am changing the class of service of panasonic pbx extension. ... ref UserRec userrec); } 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++ - enable_if in template Parameters Creates Template Redefinition Error

In this answer what I really wanted to do is define a typename in my template parameters which could be used in ... build for any given call? 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 get the contents of an std::string into a CFData object?

I've got a function that returns a std::string object. I'm working with Cocoa/CoreGraphics and I need a way to ... to do please let me know. 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++ - Knight's Tour backtracking infinite loop

I'm trying to write code for the Knight's Tour: A knight's tour is a sequence of moves of a knight on a chessboard ... ); cin.get(); 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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877 views

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c++ - Why is CreateFile failing to open a file across a network share?

I wrote a small program which frequently opens small, user text files and until now haven't encountered any ... Related: my follow up 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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811 views

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c++ - How to change console window style at runtime?

I'm making a game in console application and I want to prevent user resizing and maximizing window. How can I do this using HWND? See Question&Answers more detail:os...

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

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828 views

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c++ - Why can't I read and append with std::fstream on Mac OS X?

Consider the following C++ program, which takes a file and prints each line. It's a slice of a larger ... ! Can anyone solve this mystery? See Question&Answers more detail:os...

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

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942 views

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c++ - c++11: Calling a variadic function with the elements of a vector

There are plenty of questions about how to call a variadic function with the elements of a tuple. e.g: How do I expand ... args[0], args[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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