General C++ Programming - C++ Forum

by malibor

Potentially-evaluated expressions

An expression is potentially evaluated unless it is the operand of the sizeof, noexcept, typeid, de...

[19 replies] Last: [quote=malibor] static_assert is a good trick to see if it's evaluate... (by Peter87)

by JUANDENT

parsing durations using %q or %Q??

cannot parse durations using %q or %Q...e.g. std::chrono::duration<long long, std::milli> dur{ ...

[5 replies] Last: Maybe something like: #include <chrono> #include <iostream> #includ... (by seeplus)

by JUANDENT

parsing a formatted string

using the format library in C++20, and having done this: int val = 25; string str = std::format( ...

[6 replies] Last: To just obtain a number from std::string, there are the stoxxx functio... (by seeplus)

by JUANDENT

I don't understand ISO week

Please explain why Sunday jan 1, 2023 prints as 52 using %V -- why is that different to week 1? ...

[1 reply] : [quote=JUANDENT]week 1 starts with Jan 1 for every year... Nope. Eve... (by Peter87)

by JUANDENT

now() returns same as current_zone()->to_local(now())

Hi, system_clock::now() returns the same value as chr::current_zone()->to_local(now()); I expected...

[1 reply] : A quick search reveals: https://en.cppreference.com/w/cpp/chrono/utc_... (by TheIdeasMan)

by malibor

Should destructors be noexcept?

I'm working on a library which whose classes are almost all hierarchical, problem is that if upmost ...

[13 replies] Last: There is nothing in the C++ standard that demands that this should ge... (by malibor)

by shekharsahoo

Need Help to find the error

I have below code, for functor. But this is giving compilation error in VS17. #include <iostream...

[3 replies] Last: Now I understand, the problem. Yes thanks to both of you for the clari... (by shekharsahoo)

by JUANDENT

where can I find trim() in std C++?

I expected std::string to have a member function trim() but it does not. How to accomplish this?? ...

[4 replies] Last: Using ranges, then possibly something like this which will trim white-... (by seeplus)

by JUANDENT

is this object dangling?

hi, I have this code assert(ltrim_copy(str) == "¢4,500.55"); // line 1 ltrim_co...

[1 reply] : it's OK and it is destroyed when assert returns. (by malibor)

by LukeProducts

Neuronal Network not working properly..

Dear Community, I'm wondering what I'm doing wrong when it comes to building neural networks and I ...

[4 replies] Last: You implementation is missing a "Neuron" class, "Layer" class, "Synaps... (by malibor)

by JUANDENT

how can a function name be an lvalue?

take this function: int abs(int a) { return a < 0 ? -a : a; } abs is supposed to...

[8 replies] Last: [quote=seeplus]In my mind (and the language lawyers will probably squa... (by Peter87)

by Cplusc

blockMesh generator

Following my question regarding hexahedral mesh generation in a domain using the STL file representi...

[10 replies] Last: > Actually this is not a big code at all Big enough for you to dump on... (by salem c)

by seeplus

Age calculation

With C++20/23 std::chrono and a birthdate as either type sys_days or year_month_day, is there any 'e...

[1 reply] : We've come up with this: struct Age { unsigned years {}; unsigned... (by seeplus)

by Cplusc

Building project from github

I'm trying to build this project https://github.com/hemelb-codes/hemelb. This project has several ...

[4 replies] Last: vcpkg is used with Visual Studio. step 1: install all deps with corre... (by malibor)

by malibor

Force implicit conversion of a string literal in templated class?

The code below doesn't compile because string literal instead of std::string is given to construct...

[3 replies] Last: C++17! https://en.cppreference.com/w/cpp/language/class_template_argu... (by mbozzi)

by Cplusc

generate mesh inside .STL file

I have some STL files (usually aneurysm) and I'm using Lattice Boltzmann Method for my simulation an...

[18 replies] Last: I would strongly appreciate any idea on my way of generating mesh insi... (by Cplusc)

by seeplus

year_month_day vs sys_days

When dealing with dates - year, month, day (not times) - either year_month_day or sys_days can be us...

[9 replies] Last: [quote=seeplus]When do you get 8 for sys_days? libstdc++ (64-bit) htt... (by Peter87)

by seeplus

Chrono date literals

Since C++20 there has been the d and y literals defined in <chrono> - but no m. This seems to be ...

[4 replies] Last: I get forward thinking & future planning, but c++ has no business stan... (by jonnin)

by JUANDENT

How can I find the maximium number of decimal digits representable in a double?

What is the maximum precision of double? numeric_limits<double>::????? default precision is 6 digi...

[3 replies] Last: https://en.cppreference.com/w/cpp/types/numeric_limits/digits10 (by Peter87)

by allenmaki

output will show only the end.

Hello everybody. I really thank you for helping me to go back to programming in C++. You know I a...

[6 replies] Last: What exactly do you want to know? Let's say your terminal/cmd has 100 ... (by Ganado)

General C++ Programming - March 2023

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