fn main() {

let x = Box::new(-1);

let x1 = i32::abs(*x); //explicit dereference

let x2 = x.abs(); //implicit dereference

assert_eq!(x1, x2);

```
let r = &x;
let r1 = i32::abs(**r);//abs(i32) so we need to dereference
let r2 = r.abs();//syntantic sugar
assert_eq!(x1, x2);
let s = String::from("Sabin");
let s1 = str::len(&s);
let s2 = s.len();
println!("{} {}", s1, s2);
```

}