C++: What are the key differences between C++17, C++20, and C++23?

1// C++17
2auto [x, y] = std::pair(1, 2);  // Structured binding
3if constexpr (sizeof(void*) == 8) { /* ... */ }
4std::optional<int> opt = 42;
5
6// C++20
7template<typename T>
8concept Numeric = std::is_arithmetic_v<T>;
9
10auto evens = v | std::views::filter([](int n) { return n % 2 == 0; });
11
12std::coroutine_handle<> handle;
13
14std::cout << std::format("{} + {} = {}", 1, 2, 3);
15
16// C++23
17std::expected<int, Error> result = parse(input);
18
19std::println("Hello {}!", "world");
20
21std::flat_map<std::string, int> fm;
22
23std::generator<int> gen() {
24    co_yield 1;
25}