Function swap 

pub const fn swap<T>(x: &mut T, y: &mut T)

Swaps the values at two mutable locations, without deinitializing either one.

• If you want to swap with a default or dummy value, see take.
• If you want to swap with a passed value, returning the old value, see replace.

Examples

use std::mem;

let mut x = 5;
let mut y = 42;

mem::swap(&mut x, &mut y);

assert_eq!(42, x);
assert_eq!(5, y);