#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let x = 42;
    assert_eq!(format!("{x:b}"), "101010");
    assert_eq!(format!("{x:#b}"), "0b101010");
    assert_eq!(format!("{:b}", - 16), "11111111111111111111111111110000");
}