Recent questions tagged c++

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c++ - Getting base name of the source file at compile time

I'm using GCC; __FILE__ returns the current source file's entire path and name: /path/to/file.cpp. Is ... making its way into the executable. 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++ - To support move semantics, should function parameters be taken by unique_ptr, by value, or by rvalue?

One of my function takes a vector as a parameter and stores it as a member variable. I am using const ... approach should I avoid and 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++ - Accept any kind of callable and also know argument type

I'm not sure if it's possible, so that's what I want to find out. I'd like to create a function which ... need to know what type he/she expects. See Question&Answers more detail:os...

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

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878 views

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c++ - windows form CLR application in Visual studio 2012 RC?

quick question, im just trying out VS2012 and trying to make a c++.net app but for the life of me i cant ... Or is it something i must download? See Question&Answers more detail:os...

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

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341 views

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c++ - is it possible to use QtConcurrent::run() with a function member of a class

I can't seem to be able to associate QtConcurrent::run() with a method (function member of a class) only with ... me and would like some input. 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 are Unrestricted Unions proposed in C++11?

I gather unrestricted unions as one of the functionality being put forth in C++11. Can anyone please explain ... and the advantages it provides? See Question&Answers more detail:os...

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

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291 views

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c++ - How to pass two dimensional array of an unknown size to a function

I want to make class library, a function which its parameter is a matrix of unknown size, and the user will ... Operations to do on matrix } See Question&Answers more detail:os...

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

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786 views

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c++ - Error: Qualifiers dropped in binding reference of type x to initializer of type y

why does the following throw this error: IntelliSense: qualifiers dropped in binding reference of type "string &" ... changes to the variable? 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++ - Can variadic template template parameter be partial-specialized?

Consider the following program: template<template<typename ...> class> struct foo {}; template<template<typename> class C ... /none of them ? ) See Question&Answers more detail:os...

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

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325 views

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c++ - What kind of dead code can GCC eliminate from the final output?

I have always been told that compiler is sufficient smart to eliminate dead code. Much of the code that ... facilitate dead code elimination? See Question&Answers more detail:os...

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

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309 views

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c++ - How to link against debug versions of libc and libstdc++ in GCC?

I am aware of this question, but it does not appear to work for me. For the setup, take a simple C++ ... and how would I link against 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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884 views

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c++ - Qt: does "new without delete" cause memory leaks with controls?

I was looking at Qt example here: and inside the constructor, they have: Window::Window() { editor = new ... when it goes out of scope? See Question&Answers more detail:os...

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

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327 views

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c++ - How to find nearest next/previous double value (numeric_limits::epsilon for given number)

The title is quite self-explanatory, input is given double value, and I want to add/substract the smallest amount 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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187 views

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c++ - What is the Rule of Four (and a half)?

For properly handling object copying, the rule of thumb is the Rule of Three. With C++11, move semantics are a ... } private: int* resource; }; See Question&Answers more detail:os...

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

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294 views

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c++ - Benefits of vector<char> over string?

This question is related to, but not quite the same as, this question. Are there any benefits to using std:: ... a vector compared to a 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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255 views

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c++ - How to check if given number is divisible of 15 in fastest way?

Division in processor takes much time, so I want to ask how to check in fastest way if number is divisible of ... for answer without / and %. See Question&Answers more detail:os...

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

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335 views

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c++ - Why can't I initialize my static data member in my constructor

I read the answer in parashift but I need bit details as to why compiler won't allow to define static member variable in constructor. See Question&Answers more detail:os...

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

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283 views

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c++ - How can I shuffle bits efficiently?

I need to shuffle a 16 bit unsigned integer in a way that the even indexes land in the lower byte, ... and shifting each individual bit? See Question&Answers more detail:os...

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

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290 views

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c++ - Why does virtual assignment behave differently than other virtual functions of the same signature?

While playing with implementing a virtual assignment operator I have ended with a funny behavior. It is not a ... to this odd behavior? See Question&Answers more detail:os...

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

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240 views

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c++ - temporary lifetime in range-for expression

Consider a simple class A that can be used as a range: struct A { ~A() { std::cout << "~A "; } ... without resorting to making a copy of the A? See Question&Answers more detail:os...

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

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1.2k views

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c++ - How to get rid of "unsafe" warnings / errors in Visual Studio (strcpy, sprintf, strdup)

I'm trying to get rid of some compiler warnings that say strcpy, sprintf, etc are unsafe. I get why they're unsafe ... the thing in the C++ 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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251 views

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c++ - Is it legal to call member functions after an object has been explicitly destroyed but before its memory was deallocated?

I have this code: struct data { void doNothing() {} }; int main() { data* ptr = new data(); ptr- ... member function call be legal in this case? See Question&Answers more detail:os...

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

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318 views

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c++ - Include .cpp instead of header(.h)

There are some cases when we include .cpp file instead of standard header file (.h), for example: #include ... What about the compilation time? See Question&Answers more detail:os...

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

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267 views

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c++ - How does std::endl not use any brackets if it is a function?

The question is pretty much in the title. According to C++ Reference, std::endl is actually a function. ... any brackets when calling too? See Question&Answers more detail:os...

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

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262 views

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c++ - How do I build Boost 1.55 with MinGW?

I have downloaded Boost 1.55 and MinGW. The console answers me that I haven't any command. I can't understand how ... 3861!! How can I build 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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295 views

1 answer

c++ - convert Rcpp::CharacterVector to std::string

I am trying to open a file within an Rcpp function, so I need the file name as a char* or std:: ... a file from the Rcpp function argument? See Question&Answers more detail:os...

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

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294 views

1 answer

c++ - How to construct an std::array with index sequence?

How can I construct an std::array with an index sequence, or a lambda which depends on a sequential index? std::iota and ... 1.0}}; 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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673 views

1 answer

c++ - How to check if template argument is a callable with a given signature

Basically, what I want to achieve is compile-time verification (with possibly nice error message) that registered ... <Signature> callback; }; See Question&Answers more detail:os...

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

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