//@ In the following, we will look into the iterator mechanism of Rust and make our `BigInt` compatible
//@ with the `for` loops. Of course, this is all about implementing certain traits again. In particular,
-//@ an iterator is something that implements the `Iterator` trait. As you can see in [the documentation](http://doc.rust-lang.org/stable/std/iter/trait.Iterator.html),
+//@ an iterator is something that implements the `Iterator` trait. As you can see in [the documentation](https://doc.rust-lang.org/stable/std/iter/trait.Iterator.html),
//@ this trait mandates a single function `next` returning an `Option<Self::Item>`, where `Item` is an
//@ associated type chosen by the implementation. (There are many more methods provided for `Iterator`,
//@ but they all have default implementations, so we don't have to worry about them right now.)
// ## Iterator conversion trait
//@ If you closely compare the `for` loop in `main` above, with the one in `part06::vec_min`, you will notice that we were able to write
//@ `for e in v` earlier, but now we have to call `iter`. Why is that? Well, the `for` sugar is not actually tied to `Iterator`.
-//@ Instead, it demands an implementation of [`IntoIterator`](http://doc.rust-lang.org/stable/std/iter/trait.IntoIterator.html).
+//@ Instead, it demands an implementation of [`IntoIterator`](https://doc.rust-lang.org/stable/std/iter/trait.IntoIterator.html).
//@ That's a trait of types that provide a *conversion* function into some kind of iterator. These conversion traits are a frequent
//@ pattern in Rust: Rather than demanding that something is an iterator, or a string, or whatever; one demands that something
//@ can be converted to an iterator/string/whatever. This provides convenience similar to overloading of functions: The function