Recent questions tagged C++

0 votes

259 views

1 answer

c++ - What's the purpose of using braces (i.e. {}) for a single-line if or loop?

I'm reading some lecture notes of my C++ lecturer and he wrote the following: Use Indentation // OK Never ... benefit of using the 1st version? See Question&Answers more detail:os...

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

0 votes

284 views

1 answer

c++ - How does std::move() transfer values into RValues?

I just found myself not fully understanding the logic of std::move(). At first, I googled it but seems like ... , that will be awesome too). See Question&Answers more detail:os...

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

0 votes

188 views

1 answer

c++ - Which Boost features overlap with C++11?

I put my C++ skills on the shelf several years ago and it seems now, when I need them again, the landscape ... boost ones and which better not? See Question&Answers more detail:os...

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

0 votes

185 views

1 answer

c++ - Why does GCC generate 15-20% faster code if I optimize for size instead of speed?

I first noticed in 2009 that GCC (at least on my projects and on my machines) have the tendency to ... correlation with the execution times. See Question&Answers more detail:os...

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

0 votes

213 views

1 answer

c++ - Vector assignment crashing

vector< vector<int> > resizeVector(vector< vector<int> > m) { vector< vector<int> > newMatrix; int i,j; for (i ... here, and I am not sure why. See Question&Answers more detail:os...

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

0 votes

399 views

1 answer

c++ - WaitForInputIdle doesn't work for starting mspaint programmatically

I'm trying to open "mspaint" and find handle of it right after it has been initialized. But FindWindow returns ... mspaint program"); return; } See Question&Answers more detail:os...

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

0 votes

505 views

1 answer

c++ - inlining failed in call to always_inline '__m256d _mm256_broadcast_sd(const double*)'

I'm trying to run a Visual Studio cpp project created by a friend of mine. I'm trying to run the file ... add -mavx to the compiler invocation? See Question&Answers more detail:os...

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

0 votes

267 views

1 answer

c++ - How to store functional objects with different signatures in a container?

So imagine we had 2 functions (void : ( void ) ) and (std::string : (int, std::string)) and we could have ... >["my_method_hello"]("Tim", 25);). See Question&Answers more detail:os...

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

0 votes

173 views

1 answer

c++ - Scope vs life of variable in C

Could someone exactly explain the concept of scope and life of variable in C. Is it different in C++? I'm confused between scope and life. See Question&Answers more detail:os...

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

0 votes

412 views

1 answer

c++ - What (actually) happens, when a function with the warning "control reaches end of non-void function" is called?

I know what this message means, I just wondered why it is not an error message, but just a warning? What ... value and nothing more can happen? See Question&Answers more detail:os...

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

0 votes

339 views

1 answer

c++ - Why is sizeof(std::string) only eight bytes?

Why is std::string's size, as determined by sizeof(std::string), yield 8? I thought it should be more ... and probably a char* for characters. See Question&Answers more detail:os...

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

0 votes

202 views

1 answer

c++ - String Literals

I have few doubts about string literals in c++. char *strPtr ="Hello" ; char strArray[] ="Hello"; Now strPtr ... ? (in data section of program) See Question&Answers more detail:os...

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

0 votes

311 views

1 answer

c++ - gcc/g++: "No such file or directory"

g++ gives me errors of the form: foo.cc:<line>:<column>: fatal error: <bar>: No such file or directory ... , once and for all; a FAQ. See Question&Answers more detail:os...

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

0 votes

293 views

1 answer

c++ - Using assignment as a condition expression?

Consider: if (a=5) { /* do something */ } How does the assignment work as a condition? Is it based on non-zero value of l-value? See Question&Answers more detail:os...

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

0 votes

241 views

1 answer

c++ - Unsequenced value computations (a.k.a sequence points)

Sorry for opening this topic again, but thinking about this topic itself has started giving me an Undefined Behavior ... to built-in operators." See Question&Answers more detail:os...

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

0 votes

329 views

1 answer

c++ - Why are redundant scope qualifications supported by the compiler, and is it legal?

I tested on two compilers, and was surprised to see both support the following definition without complaint: class ... + LLVM were the compilers See Question&Answers more detail:os...

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

0 votes

320 views

1 answer

c++ - Why do we need typename here?

template<class T> class Set { public: void insert(const T& item); void remove(const T& item); private: std::list ... in the remove() is needed? See Question&Answers more detail:os...

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

0 votes

276 views

1 answer

c++ - 😃 (and other Unicode characters) in identifiers not allowed by g++

I am ?? to find that I cannot use ?? as a valid identifier with g++ 4.7, even with the -fextended- ... kind of support do other compilers have? See Question&Answers more detail:os...

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

0 votes

223 views

1 answer

c++ - Why statements cannot appear at namespace scope?

Any idea on which rule in standard states the statements like this: p++; //where 'p' is pointer to ... not just an explanation if possible. See Question&Answers more detail:os...

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

0 votes

167 views

1 answer

c++ - Spirit-Qi: How can I write a nonterminal parser?

I want to write a parser (as a qi extension) which can be used via my_parser(p1, p2, ...) where p1, p2, ... ... qi = boost::spirit::qi; namespace qitoo = mxc::qitoo; using iter...

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

0 votes

330 views

1 answer

c++ - SetWindowsHookEx for WH_MOUSE

I've got some code into my hands that prints coordinates of the mouse globally (using WH_MOUSE_LL). My target is ... ); else return 1; } See Question&Answers more detail:os...

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

0 votes

162 views

1 answer

c++ - Get attribute by name

I have a struct definition with about 25 elements struct X { field 1; field 2; .. }; and I'm trying to fill it ... "]); and put it into a loop? See Question&Answers more detail:os...

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

0 votes

165 views

1 answer

c++ - Understanding the List Operator (%) in Boost.Spirit

Can you help me understand the difference between the a % b parser and its expanded a >> *(b >> ... though phrase_parse returned true somehow? See Question&Answers more detail:os...

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

0 votes

316 views

1 answer

c++ - Undefined behavior causing time travel

One example of this article from a msdn blog made me ticker: It says that this function: void unwitting(bool ... the run time enters UB? See Question&Answers more detail:os...

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

0 votes

236 views

1 answer

c++ - When instantiating a template, should members of its incomplete argument types be visible?

In the following example, A has a member typedef Instantiate which causes the instantiation of B<A>. template< ... definition of the template. See Question&Answers more detail:os...

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

0 votes

657 views

1 answer

c++ - How to include compiler flags in Visual Studio Code?

I have a program that I am trying to run in the Visual Studio Code debugger that uses fftw functions. It ... way I have asked this question. See Question&Answers more detail:os...

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

0 votes

410 views

1 answer

c++ - Operator overload which permits capturing with rvalue but not assigning to

Is it possible to design and how should I make overloaded operator+ for my class C to have this possible: C&& c ... . So how double does this? See Question&Answers more detail:os...

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

0 votes

241 views

1 answer

c++ - High delay in RS232 communication on a PXA270

I'm experiencing a long delay (1.5ms - 9.5ms) in a RS232 communication on a PXA270 RISC PC/104. I want ... very much in advance for your help. See Question&Answers more detail:os...

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

Categories

Just Browsing Browsing

Most popular tags