Code shared from the Rust Playground

playground.rs

#[derive(Debug)]
struct Tokens {
    idx: i8,
    val: i8,
    chr: char,
}

impl Tokens {
    fn new(idx: i8, val: i8, chr: char) -> Tokens {
        Tokens {
            idx: idx,
            val: val,
            chr: chr,
        }
    }

    fn update(&mut self, chr: char) {
        self.chr = chr;
    }
}

fn make_board() -> Vec<Tokens> {
    let mut count = 0;
    let mut spots = Vec::<Tokens>::new();
    let values = [4, 9, 2, 3, 5, 7, 8, 1, 6];
    for val in &values {
        let tok = Tokens::new(count, *val, ' ');
        spots.push(tok);
    }
    spots
}

fn main() {
    let board = make_board();
    println!("{:?}", board);
}