Function bubble_sort2

code/chapter06/bubble_sort.rs:18–28

(nums: &mut [i32])

}

fn bubble_sort2(nums: &mut [i32]) {
    let mut len = nums.len() - 1;
    while len > 0 {
        for i in 0..len {
            if nums[i] > nums[i+1] {
                nums.swap(i, i+1);
            }
        }
        len -= 1;
    }
}

fn bubble_sort3(nums: &mut [i32]) {
    let mut compare = true;