Rust中的嵌套默认结构值

struct Address {
    street: String,
    city: String,
    country: String,
}

struct Person {
    name: String,
    age: u32,
    address: Address,
}

impl Default for Address {
    fn default() -> Self {
        Address {
            street: String::from("Unknown"),
            city: String::from("Unknown"),
            country: String::from("Unknown"),
        }
    }
}

impl Default for Person {
    fn default() -> Self {
        Person {
            name: String::from("Unknown"),
            age: 0,
            address: Address::default(),
        }
    }
}

fn main() {
    let person: Person = Default::default();
    println!("Name: {}", person.name);
    println!("Age: {}", person.age);
    println!("Street: {}", person.address.street);
    println!("City: {}", person.address.city);
    println!("Country: {}", person.address.country);
}