任何遵循Equatable的類型，都需要實(shí)現(xiàn)方法static func ==(lhs: Self, rhs: Self) -> Bool在這個(gè)方法內(nèi)按照指定的值和值間對比關(guān)系返回true或是false，外部表現(xiàn)為==或是!=的結(jié)果

struct Human: Equatable {
    var name: String
    var age = 5
    
    static func == (lhs: Self, rhs: Self) -> Bool {
        return lhs.name == rhs.name
    }
}

let tom = Human(name: "tom", age: 5)
let tim = Human(name: "tim", age: 6)
tom == tim // false

let man1 = Human(name: "tom", age: 5)
let man2 = Human(name: "tom", age: 6)
man1 == man2 // true