Recent questions tagged C++

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I'm trying to implement a map with a lambda function in C++11 as such std::map<int, int, [](const ... declaration before ;' token Any advice? 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 remove filename from path string

I have const char *pathname = "..somepathsomemorepathsomefile.ext"; how to transform that into "..somepathsomemorepath" ? 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++ - override on non-virtual functions

The C++11 FDIS it says If a virtual function is marked with the virt-specifier override and does not ... front of the example's functions 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++ - g++ error: ‘stricmp’ was not declared in this scope (but OK for 'strcmp')

I am trying to compile the following very very simple piece of source code: #include <cstring> // #include < ... std' but nothing helped. 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++ - Compiling with Clang using Libc++ undefined references

The first couple are too long to reference. I get this error when I try to compile clang++ -stdlib=libc++ ../ ... 11 -stdlib=libc++ -lc++abi. 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++ - 'X is not a template' error

I'm having trouble declaring a template class. I've tried an number of ill-readable and non-sensical combinations. ... < CIPHER > m_cipher; }; 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++ - Portable code - bits per char

I know that the C/C++ standards only guarantee a minimum of 8 bits per char, and that theoretically 9/16/42/ ... ? And is my above surmise true? 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 SCARY iterators?

I'm reading the VC11 Blog on VC11's C++11 features when I've come up to the SCARY iterators topic. What ... affect my C++ coding experience? 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++ - abs vs std::abs, what does the reference say?

Beware, I am talking about ::abs(), not std::abs() According to the cplusplus.com website, abs is supposed ... it includes math.h silently)? 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 avoid use of goto and break nested loops efficiently

I'd say that it's a fact that using goto is considered a bad practice when it comes to programming in C/C++. ... it's good to use it? Thank you 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 enable C++17 on Mac?

I am able to update gcc on Linux to get -std=c++17 but cannot do the same on Mac. Is there a version of ... +17 on my Mac? Please help. 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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c++ - Should I mark a compiler-generated constructor as constexpr?

Is there a difference between doing: X() = default; and constexpr X() = default; Default-constructing the class ... I use one over 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++ - How can a variable be used when its definition is bypassed?

In my mind, always, definition means storage allocation. In the following code, int i allocates a 4-byte ( ... ; //prints 3 successfully } 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 difference between && and & with bool(s)?

In C++, is there any difference between doing && (logical) and & (bitwise) between bool(s)? bool val1 = ... Is a bitwise and of bools portable? 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++ - Does the equal sign make a difference in brace initialization? eg. 'T a = {}' vs 'T a{}'

Here are two ways to initialize a variable in C++11: T a {something}; T a = {something}; I tested ... is there any difference between the two? 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 library does ld option -lrt refer to (Bionic libc)?

What does this option to ld mean? -lrt I know to some degree it means that ld is looking for the library ... a way to override this 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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c++ - Qt Creator Android error "Platform SDK installed"

I am developing Qt Cross platform application for Android, recently i have updated Qt creator and Installed new ... here resolved same issue. See Question&Answers more detail:os...

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

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446 views

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c++ - Capturing a static variable by reference in a C++11 lambda

Main question I'm trying to compile the following code with GCC 4.7.2: #include <iostream> int foo() { ... variable. Am I right about 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++ - Protobuf: Will set_allocated_* delete the allocated object?

I have this small protobuf code (simplified, only the necessary is contained): message ParamsMessage { required int32 ... anything in the docs. 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 are `&array` and `array` pointing to the same address?

Until now, I thought an array is the same as a pointer. But I found a weird case: code int array[5] ... the memory which holds the array values? 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 there a performance warning on cast pointer to bool?

Extends. I thought I was being cool when I did something like: bool hasParent() { return this->parentNode ; ... happier. Which is faster though? 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 sizeof(void()) a legal expression?

From [5.3.3/1], I found that: The?sizeof?operator shall not be applied to an expression that has function or ... in an UB and that's all? 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 is double evaluation and why should it be avoided?

I was reading that in C++ using macros like #define max(a,b) (a > b ? a : b) can result in a 'double ... in Clojure (which I can't understand). 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++ - remove unique_ptr from queue

I'm trying to figure out how/if I can use unique_ptr in a queue. // create queue std::queue<std::unique_ptr<int> ... Is there a 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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c++ - How resume the execution of a stackful coroutine in the context of its strand?

using Yield = asio::yield_context; using boost::system::error_code; int Func(Yield yield) { error_code ec; ... Func was originally spawned on? 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++ - Lambda with dynamic storage duration

According to cppreference.com, C++11 lambda literal syntax is only legal to use in direct initialization. There doesn' ... captures a copy of o. 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 get thread state (e.g. suspended), memory + CPU usage, start time, priority, etc

How do I get the information if a thread has been suspended with SuspendThread(). There is no API that gives this ... the code to work on XP. 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++ - C++11 compiler generated functions

Say a class class Piece {} ; If I'm correct that should be equivalent to : class Piece { //C++ 03 ... functions, when not provided by user ? See Question&Answers more detail:os...

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

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