rust code example - fibonacci generator

fib.rs

fn fib(n: usize) -> Vec<u64> {
    let mut fibs = Vec::new();

    while fibs.len() < n {
        let current = match fibs.len() {
            0 => 0,
            1 => 1,
            _ => {
                fibs.iter().rev().take(2).sum()
            }
        };
        fibs.push(current);
    }

    fibs
}

fn fib2(n: usize) -> Vec<usize> {
    let mut fibs = Vec::new();
    let mut cnt = 0;
    let mut current = 0;
    let mut prev1 = 0;

    while cnt < n {
        match cnt {
            0 => {
                current = 0;
            },
            1 => {
                current = 1;
            },
            2 => {
                prev1 = current;
                current = 1;
            },
            _ => {
                let prev2 = prev1;
                prev1 = current;
                current = prev2 + prev1;
            }
        };
        fibs.push(current);
        cnt += 1;
    }

    fibs
}

fn main() {
    // fib
    assert_eq!(fib(1), vec![0]);
    assert_eq!(fib(2), vec![0, 1]);
    assert_eq!(fib(3), vec![0, 1, 1]);
    assert_eq!(fib(4), vec![0, 1, 1, 2]);
    assert_eq!(fib(5), vec![0, 1, 1, 2, 3]);
    assert_eq!(fib(6), vec![0, 1, 1, 2, 3, 5]);
    assert_eq!(fib(7), vec![0, 1, 1, 2, 3, 5, 8]);
    assert_eq!(fib2(8), vec![0, 1, 1, 2, 3, 5, 8, 13]);
}