#![allow(unused_variables)]
fn main() {
    assert_eq!(format!("Hello {:<5}!", "x"), "Hello x    !");
    assert_eq!(format!("Hello {:-<5}!", "x"), "Hello x----!");
    assert_eq!(format!("Hello {:^5}!", "x"), "Hello   x  !");
    assert_eq!(format!("Hello {:>5}!", "x"), "Hello     x!");
}