---
title: "Rust I"
date: "2020.03.04"
slug: "posts/rust-i"
archive: true
---


so i tried to implement insertion sort using rust, why ? im bored but i find something interesting stuff

  ```rs
    let mut arr = [5,3,2,4,1,6];
    for n in 1..arr.len() {
      let key = arr[n];
      let mut i = n - 1;
      while i >= 0 && arr[i] > key {
        arr[(i+1)] = arr[i];
        i -= 1;
      }
      arr[(i+1)] = key;
    }
    println!('{:?}', arr);
  ```

it's basic stuff no sugarcoated , buuuut it failed of course it and the compiler said
  ```
  warning: comparison is useless due to type limits
  --> insertion_sort.rs:26:11
   |
26 |     while i >= 0 && arr2[i] > key {
   |           ^^^^^^
   |
   = note: `#[warn(unused_comparisons)]` on by default
   ```

well my lil snailass brain thought "unused comparison??!! what ?