Return 1 if `v` is either 1, 3 or 5. Return 2 if `v` is either 0, 2 or 4. Return 3 in any other situation. The match expression should have three arms

Return 1 if `v` is between 0 (inclusive) and 100 (exclusive). Return 2 if `v` is between 100 (inclusive) and 200 (exclusive). Return 3 in any other si

Return 1 if `v` is in the first half of the English alphabet (`a-n` or `A-N`) (uppercase *or* lowercase). Return 2 if `v` is in the second half of the

Check if the character in `v` is a digit (0-9). The match expression should have two arms.

Check if `v` is a digit. If it is, return a u32 containing the numerical value of that digit (wrapped in `Some`). Use a match expression. Hint: it ma

Run this file with `cargo test --test 04_iter_exercises`. TODO: Implement a function called `keep_even`, which will receive something that can be turn