An iterative & recursive implementation of Fibbonaci in Rust.

fibonaci.rs

fn fib(n: i32) {
    let mut a: u128 = 1;
    let mut b = 1;
    for i in 0..n {
        if i == 0 || i == 1{
            print!("{} ", a);
            continue
        }
        let c = a;
        a = b;
        b = a + c;

        print!("{} ", b)
    }
    println!()
}

fn fib_r(n: i32) -> i32{
    if n == 0 {
        return 0;
    }
    if n == 1 {
        return 1;
    }
    let num = fib_r(n - 1) + fib_r(n - 2);
    return num;
}

fn print_fib_r_2(start: i32, stop: i32, cache: &mut Vec<i32>, out_result: &mut Vec<i32>) {
    let mut value: i32 = cache[start as usize];
    if value == -1 {
        value = fib_r(start);
        cache[start as usize] = value;
    }

    out_result[(start - 1) as usize] = value;
    if start < stop {
        print_fib_r_2(start + 1, stop, cache, out_result)
    }
}

fn print_fib_r(n: i32, cache: &mut Vec<i32>) -> Vec<i32> {
    let mut result: Vec<i32> = Vec::new();

    for i in 0..n  {
        result.push(-1);
    }
    print_fib_r_2(1, n, cache, &mut result);

    return result
}


fn main() {
    fib(15);
    let mut cache = Vec::new();
    for _ in 0..100 {
        cache.push(-1)
    }

    let data = print_fib_r(25, &mut cache);
    println!();
    for i in data {
        print!("{} ", i)
    }
    let data = print_fib_r(40, &mut cache);
    println!();
    for i in data {
        print!("{} ", i)
    }
}