Curriculum Ownership & borrowing Shared borrowing exercise 2 · mcq-explain

Shared borrowing

Given fn log(s: &String) and let name = String::from("paul");, pick the call site that borrows name and lets it stay usable afterward.

log(&name); — takes a shared reference; name stays usable.

log(*name); — dereferences name, but name isn't a reference yet.

log(name); — moves the String into log; name is no longer usable.

log(name.clone()); — works but wastes a heap allocation; borrow instead.

About this theme

Borrowing is how Rust lets code inspect data without taking it. &T references are shared, read-only views whose owner remains somewhere else. Planned exercises: 1. choose &String over String for a read helper. 2. recognise call-site borrowing with &name. 3. choose dereference-free field or method access. 4. fill an & parameter. 5. fill an & argument. 6. write a read-only helper. 7. write a caller that keeps using the owner afterward. 8. translate a TS read helper. 9. fix a function that accidentally takes ownership.