如何使用println!()打印命名参数的子项？

#[derive(Debug)]
struct Person {
    name: String,
    age: u8,
    address: Address,
}

#[derive(Debug)]
struct Address {
    city: String,
    zipcode: String,
}

fn main() {
    let person = Person {
        name: String::from("Alice"),
        age: 30,
        address: Address {
            city: String::from("Wonderland"),
            zipcode: String::from("12345"),
        },
    };

    // 使用模式匹配来打印命名参数的子项
    if let Some((city, _zipcode)) = get_city(&person) {
        println!("The city is: {}", city);
    }

    // 直接访问字段来打印命名参数的子项
    println!("The city is: {}", person.address.city);
}

fn get_city(person: &Person) -> Option<(&String, &String)> {
    Some((&person.address.city, &person.address.zipcode))
}

#[derive(Debug)]
enum Location {
    City(String),
    Town(String),
}

fn main() {
    let location = Location::City(String::from("Metropolis"));

    // 使用模式匹配来打印命名参数的子项
    match location {
        Location::City(city) => println!("The city is: {}", city),
        Location::Town(town) => println!("The town is: {}", town),
    }
}