Iterate over vector of numbers

---

examples/iterators/iterator-over-vector-of-numbers/src/main.rs

fn main() {
    let numbers = vec![1, 2, 3];

    println!("{:?}", numbers);

    for n in &numbers {
        println!("{}", n);
    }
    println!("{:?}", numbers);
}

[1, 2, 3]
1
2
3
[1, 2, 3]