#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::net::Ipv4Addr;
fn main() {
    let localhost = Ipv4Addr::new(127, 0, 0, 1);
    assert_eq!("127.0.0.1".parse(), Ok(localhost));
    assert_eq!(localhost.is_loopback(), true);
    assert!("012.004.002.000".parse::< Ipv4Addr > ().is_err());
    assert!("0000000.0.0.0".parse::< Ipv4Addr > ().is_err());
    assert!("0xcb.0x0.0x71.0x00".parse::< Ipv4Addr > ().is_err());
}