fn sum(xs: &[i32]) -> i32 {
    let mut t: i32 = 0;
    for x in xs {
        t += x;
    }
    t
}

fn main() {
    let v: Vec<i32> = vec![1, 2, 3, 4];
    println!("{}", sum(&v));
    println!("{}", v.len());
    println!("{}", v[2]);
    println!("{:?}", v);
    let mut w: Vec<i32> = vec![];
    w.push(9);
    w.push(8);
    println!("{:?} {}", w, w.len());
}