use std::collections::HashSet;

#[derive(Debug)]
struct Z<'a> {
    name: String,
    hashset: &'a HashSet<&'a str>,
}

fn main() {
    let mut books = HashSet::new();

    books.insert("A Dance With Dragons");
    books.insert("To Kill a Mockingbird");
    books.insert("The Odyssey");
    books.insert("The Great Gatsby");

    let mut movies = HashSet::new();

    movies.insert("A Dance With Dragons");
    movies.insert("To Kill a Mockingbird");
    movies.insert("The Matrix");

    let z = Z{name: "Movies".to_string(), hashset: &movies};

    let union = &books ^ &movies;
    println!("{:?}", union);

    let hashsets = vec![&books, &movies];
    println!("{:?}", hashsets);

    println!("{:?}", z);
}