#[derive(Debug)]
struct Demo(u32, i32);

struct Demo01{
    a: u32,
    b: i32,
}

fn main() {
    let demo = Demo(1, -1);

    let Demo(c, _) = demo;

    println!("{}", c);

    let demo01 = Demo01 {
        a: 2,
        b: -2,
    };

    let Demo01 {
        a,
        b: _,
    } = demo01;

    println!("{}", a);
}