Rust 枚举类

概述

枚举允许你定义一个类型，它可以是几个可能的变体之一。

🎯 定义枚举

enum IpAddrKind {
    V4,
    V6,
}

fn main() {
    let four = IpAddrKind::V4;
    let six = IpAddrKind::V6;
}

🎯 带数据的枚举

enum IpAddr {
    V4(u8, u8, u8, u8),
    V6(String),
}

fn main() {
    let home = IpAddr::V4(127, 0, 0, 1);
    let loopback = IpAddr::V6(String::from("::1"));
}

🎯 match 控制流

enum Coin {
    Penny,
    Nickel,
    Dime,
    Quarter,
}

fn value_in_cents(coin: Coin) -> u8 {
    match coin {
        Coin::Penny => 1,
        Coin::Nickel => 5,
        Coin::Dime => 10,
        Coin::Quarter => 25,
    }
}

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