RosettaCodeData/Task/Fibonacci-sequence/Rust/fibonacci-sequence-2.rust

use std::mem;
fn main() {
    fibonacci(0,1);
}

fn fibonacci(mut prev: usize, mut curr: usize) {
    mem::swap(&mut prev, &mut curr);
    if let Some(n) = curr.checked_add(prev) {
        println!("{}", n);
        fibonacci(prev, n);
    }
}