What is Range V3 for MakeStream::iterate()?

Question

C++ Streams has iterate() which takes an initial value, n and a function, f() then produces first n followed by f(n), f(f(n))...

auto stream = MakeStream::iterate(1245, [](int x) {
    if(x % 2 == 0) {
        return x / 2;
    } else {
        return 3 * x + 1;
    }
});

What does Range V3 have for this?

Answer 1

In range-v3 you would create such a range with view::generate:

auto stream = ranges::view::generate([x=1245]() mutable {
    auto old = x;
    if(x % 2 == 0)
        x /= 2;
    else
        x = 3 * x + 1;
    return old;
});

DEMO