Immutable Variables

Our Contional Function program uses four variables:

let alfa = 4;
let bravo = 9;

and

let charlie = 7;
let delta = 3;

Another approach is to change the values of alfa and bravo instead of creating charlie and delta. We can do that, but we need to change the way we create alfa and bravo first because Rust variables are immutalbe by default. That means that once we bind a value to them we can't change it.

For example, run this and you'll get an error that we'll discuss on the next page.

SOURCE CODE

fn main() {
  let alfa = 7;
  println!("alfa is {}", alfa);

  alfa = 9;
  println!("alfa is {}", alfa);
}

CODE RUNNER

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