insertion sort in rust

insetion_sort.rs

extern crate rand;

use rand::prelude::*;

fn main() {
  const LEN: usize = 10;
  let mut arr: [i32; LEN] = [0; LEN];
  let mut rng = thread_rng();
  for index in 0..LEN {
    arr[index] = rng.gen_range(0, 101)
  }

  // before
  println!("{:?}", &arr);

  // insertion sort
  for index in 0..LEN {
    let tmp = arr[index];
    let mut cmp_index = index;
    while cmp_index > 0 && arr[cmp_index - 1] > tmp {
      arr[cmp_index] = arr[cmp_index - 1];
      cmp_index -= 1;
    }
    arr[cmp_index] = tmp;
  }

  // after
  println!("{:?}", &arr);
}