class Person {
    int age;
    string name;
    Person(int age, String name){
        this.age = age;
        this.name = name;
    }
    void sayhi(){
        print('my name is' this.name)
    }
}

class Worker extend Person{
    int salary;
    Worker(int age, string name, int salary) : super(age, name){　　//super表示要继承父类的属性
        this.salary = salary;
    }
    @override　　//告诉编译器和程序员他是一个重写覆盖父类的方法
    void sayhi(){
　　　　　super.sayhi()　　　　//表示调用父类的sayhi方法
        print('my salary is'+ this.salary)
    }
}

void main(){
　　var p = new Person(15,'sdf');
　　p.eat();    //并不会报错
}
class Eat{
    void eat(){
        print('eat')
    }
}

class Sleep{
    void sleep(){
        print('sleep')
    }
}

class Person with Eat, sleep{
    int age;
    string name;
    person(int age, string name){
        this.age = age;
        this.name = name;
    }
    void sayhi(){
        print('hi');
    }
}

abstract class Chouxiang{
    void ya()
}

class person extend Chouxiang{
    void ya(){
        print('sdf')
    }
}