#include <coroutine>
#include <cstdio>
#include <initializer_list>

struct fiber
{
    struct promise_type
    {
        fiber get_return_object() { return {handle_type::from_promise(*this)}; }
        std::suspend_always initial_suspend() { return {}; }
        std::suspend_always final_suspend() noexcept { return {}; }
        void return_void() {}
        void unhandled_exception() {}
    };
    using handle_type = std::coroutine_handle<promise_type>;
    handle_type handle = nullptr;
    fiber(std::coroutine_handle<promise_type> h): handle(h) {}
    ~fiber() { if (handle) handle.destroy(); }
};

fiber make_fiber()
{
    for (auto i: {0, 1, 2, 3, 4})
    {
        printf("%i ", i);
        co_await std::suspend_always();
    }
}

int main()
{
    auto f = make_fiber();
    while (!f.handle.done())
        f.handle.resume();
    puts("");
}