Pass by Reference

fn main(){ let mut by\_ref = 3; // => 3 power\_of\_three(&mut by_ref); println!("{by\_ref}"); // => 9 } fn power\_of\_three(by_ref: &mut i32){ // de-referencing is important *by_ref = *by_ref * *by_ref; println!("{by\_ref}"); // => 9 }