rust 枚举

enum Color{
    Red = 0xff0000,
    Green = 0x00ff00,
    Blue = 0x0000ff,
}

enum Student{
    Boy(i32),
    Girl(i32,i32),
}

enum Opt{
    Some(i32),
    None,
}

fn main() {
    println!("red:#{:06x}",Color::Red as i32);
    println!("green:#{:06x}",Color::Green as i32);

    let x: fn(i32) -> Student = Student::Boy;
    let y: fn(i32,i32) -> Student = Student::Girl;
    let x1 = Student::Boy(11);
    let y1 = Student::Girl(11,143);

    let o = Some(33);
    let oNum = o.unwrap();//unwrap可以将Some(33)中的数字取出,如果在不确定的情况下使用unwrap,可能会导致运行时错误
    println!("oNum:{}",oNum);
    match o {
        Some(n) => println!("num:{}",n),
        None => (),
    }
}

red:#ff0000
green:#00ff00
oNum:33
num:33

//枚举可以是多种数据类型
#[derive(Debug)]
enum Color {
    Red(u32,u32,u32),
    Green(String),
    Blue{rgb: (u32,u32,u32),name: String},
}

fn value_in_color(c : Color) -> u8{
    match c {
        Color::Red(u32,_,_)=> 1,    //相同类型用_
        Color::Green(String) => 2,
        Color::Blue{rgb: (u32,_,_),name: String} => {
            print!("this is blue.");
            3
        }
    }
}

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

fn main() {
    let red = Color::Red(200,200,200);
    let green = Color::Green(String::from("green"));
    let blue = Color::Blue{rgb:(100,100,100),name:String::from("blue")};
    println!("{:?}",red);
    println!("{:?}",green);
    println!("{:?}",blue);
    println!("value is:{}",value_in_color(blue));

    let num = Some(5);
    println!("plus one:{:?}",plus_one(num));

    let t = Some(6);
    //if let 和match有点像，是一个语法糖
    if let t = Some(7){
        println!("{:?}",t.unwrap());
    }
}


Red(200, 200, 200)
Green("green")
Blue { rgb: (100, 100, 100), name: "blue" }
this is blue.value is:3
plus one:Some(6)
7