Mutable Function References

It is possible to change values in a function if you make the variable mutable and pass a mutable reference

SOURCE CODE

fn main() {

  let mut alfa = String::from("widget");

  println!("alfa {}", alfa);

  update_value(&mut alfa);

  println!("alfa {}", alfa);

}

fn update_value(value: &mut String) {
  value.push_str(" updated");
}

CODE RUNNER