Function num::range_step

Important traits for RangeStep<A>

impl<A> Iterator for RangeStep<A> where
    A: CheckedAdd + PartialOrd<A> + Clone,  type Item = A;

pub fn range_step<A>(start: A, stop: A, step: A) -> RangeStep<A> where
    A: CheckedAdd + PartialOrd<A> + Clone + Zero, 

Return an iterator over the range [start, stop) by step. It handles overflow by stopping.