Reach through nested Options in Rust
Rust interview exercise on Structs & Enums, difficulty 2 of 3. Solve it in the editor beside a worked example; the tests run the moment you do.
A user may have no profile, and a profile may have no address. Write city_of(user) that returns the city as a borrowed &str when the whole chain is present, without cloning and without unwrap.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Progress is saved in your browser, and in your account if you sign in.