#![allow(unused_variables)]
fn main() {
    assert_eq!(format!("Hello {:+}!", 5), "Hello +5!");
    assert_eq!(format!("{:#x}!", 27), "0x1b!");
    assert_eq!(format!("Hello {:05}!", 5), "Hello 00005!");
    assert_eq!(format!("Hello {:05}!", - 5), "Hello -0005!");
    assert_eq!(format!("{:#010x}!", 27), "0x0000001b!");
}