import Foundation


protocol Student{
    func sayHi()
}


class Persion:Student{
    
    var _name:String
    
    init(name:String) {
        self._name = name
    }
    
    func sayHi() {
        print("\(self._name) say hi")
    }
    
}

var per = Persion(name: "liaojianguo")

per.sayHi()