#[derive(Debug)]
enum UsState {
    NY,
    VA,
    NC,
}

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

impl Coin {

    fn value_in_cents(self) -> u32 {

        match self {
            Coin::Penny => {
                println!("lucky penny");
                1
            },
            Coin::Nickel => 5,
            Coin::Dime => 10,
            Coin::Quarter(state) => {
                println!("State quarter from {:?}", state);
                25
            },

        }

    }
}

fn plus_one(x: Option<i32>) -> Option<i32> {
    
    match x {
        None => None,
        Some(i) => Some(i + 1),
    }
}

fn main() {
    let five = Some(5);
    let six = plus_one(five);
    let none = plus_one(None);
}