trpl-zh-cn/listings/ch06-enums-and-pattern-matching/no-listing-13-count-and-announce-match/src/main.rs

#[derive(Debug)]
enum UsState {
    Alabama,
    Alaska,
    // --snip--
}

enum Coin {
    Penny,
    Nickel,
    Dime,
    Quarter(UsState),
}

fn main() {
    let coin = Coin::Penny;
    // ANCHOR: here
    let mut count = 0;
    match coin {
        Coin::Quarter(state) => println!("State quarter from {:?}!", state),
        _ => count += 1,
    }
    // ANCHOR_END: here
}