CPPAlliance

@CPPAlliance

Our mission is to make the C++ programming language accessible and useful to anyone who wishes to learn and apply the language.

CPPAlliance
@CPPAlliance
5h
auto seq = std::index_sequence<0, 1, 2>{}; auto [a, b, c] = seq; // error std::index_sequence is one of the most used metaprogramming tools. You can't destructure it with structured bindings
1
CPPAlliance
@CPPAlliance
Sep 29
std::mdspan md(data, 3, 4); md[5, 10]; // out of bounds — UB md.at(5, 10); // throws span got at() for bounds checking in C++23. mdspan was left behind until now
1
CPPAlliance
@CPPAlliance
Sep 28
auto rng = data | views::transform(expensive_parse) | views::filter(is_valid); Every time you access an element through this pipeline, expensive_parse runs again. There's no built-in way to cache the result 🧵👇
1
CPPAlliance
@CPPAlliance
Sep 25
std::integral_constant<int, 42>{} Compile time constants as types. Useful, but verbose – you have to spell the type and the value C++26 introduces constant_wrapper: same idea, less typing, and arithmetic that stays in the type system 🧵👇
3
CPPAlliance
@CPPAlliance
Sep 24
struct Point { int x, y; }; std::vector<Point> pts; std::ranges::fill(pts, Point{0, 0}); // why do I have to name the type? The compiler knows the element type. You know the element type. You still have to spell it out
4