snippet to rotate the number

vec_deque.rs

use std::collections::VecDeque;
fn main() {
    let num = 1970;
    let mut buf: VecDeque<_> = num.to_string().chars().map(|d| d.to_digit(10).unwrap()).collect();;
    for _ in 0..buf.len() {
        println!("{:?}", buf);
        let n = buf.pop_front().unwrap();
        buf.push_back(n);
    }
}