Instructor Notes

• This exercise is intended to replace the Health Statistics Exercise exercise from the original version.

• The solution includes links to several existing crates. If you have time, it can be beneficial to review their source code. In particular, non_empty_vec and vec1 take different approaches of wrapping a regular Vec.

• You can ask students who finish early to replace

pub struct NonEmptyVec<T> {
    head: T,
    tail: Vec<T>,
}

with

pub struct NonEmptyVec<T>(Vec<T>)

and fix the body of all the methods accordingly.

• Our requirements that pop should succeed even when there is a single item is different from what these crates implement. We required it since it forces pop to take ownership of self. Consuming methods are quite unique to Rust so this can lead to an interesting discussion on how to (safely) implement pop in another language.