C++2019 Online

auto result = std::vector1,2,3,4,5 | rv::filter([](int x) return x%2==0; ) | rv::transform([](int x) return x*x; ); // result = 4, 16

int main() for (const auto& entry : fs::directory_iterator(".")) auto [path, status] = std::pairentry.path(), entry.status(); if (fs::is_regular_file(status)) std::cout << "File: " << path.filename() << '\n'; c++2019

Concepts replace SFINAE with readable, checkable template requirements. #include <ranges> #include <vector> namespace rv = std::ranges::views; Embrace it

No more messy iterator pairs; lazy evaluation and chaining. generator<int> fibonacci() int a = 0, b = 1; while (true) co_yield a; // suspend and return a auto next = a + b; a = b; b = next; auto result = std::vector1

for (int f : fibonacci() | rv::take(10)) std::cout << f << ' ';

// Error: add("a", "b") – string not numeric

If you’re still writing new / delete or raw loops with index variables, . Embrace it. “C++20 feels like a new language – but still C++.� – Bjarne Stroustrup