The iterator for digits of a number.

digits.rs

pub struct Digits {
    num: u64,
    radix: u64,
}

impl Digits {
    pub fn new(num: u64, radix: u64) -> Self {
        assert!(0 < radix, "radix must be greater than zero");
        Self { num, radix }
    }
}

impl Iterator for Digits {
    type Item = u64;

    fn next(&mut self) -> Option<Self::Item> {
        if self.num == 0 {
            None
        } else {
            let digit = self.num % self.radix;
            self.num /= self.radix;
            Some(digit)
        }
    }
}

impl std::iter::FusedIterator for Digits {}