Implement Iterator in Rust
Rust interview exercise on Closures & Iterators, difficulty 3 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Implement Iterator for Fibonacci so it yields 0, 1, 1, 2, 3, 5, ... without end. Writing next() is all it takes to get take, find, filter, sum and the rest for free.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.