Rust有一个叫做match的控制流运算符，和c++这种的switch类似。

    1. enum Coin{
    2.     Penny,
    3.     Nickle,
    4.     Dime,
    5.     Quarter,
    6. }
    8. fn value_in_cents(coin:Coin)->u8{
    9.     match coin{
    10.         Coin::Penny => 1,
    11.         Coin::Nickle => 5,
    12.         Coin::Dime => 10,
    13.         Coin::Quarter => 25,
    14.     }
    15. }

    绑定值的模式

    1. #[derive(Debug)]
    2. enum UsState{
    4. }
    5. enum Coin{
    6.     Penny,
    7.     Nickle,
    8.     Dime,
    9.     Quarter,
    10. }
    11. fn value_in_cents(coin:Coin)->u8{
    12.     match coin{
    13.         Coin::Penny => 1,
    14.         Coin::Nickle => 5,
    15.         Coin::Dime => 10,
    16.         Coin::Quarter(state) => {
    17.             println!("State quarter from {:?}!",state);    
    18.         },
    19.     }
    20. }

    _ 通配符

    if let 可以用于解决match分支较少的情况