匿名对象的使用

class Pen{
    public Pen(){  }         //空构造方法
    public void show(String msg){
        System.out.println(msg);
    }
}
class Person{
    //1.定义数据成员
    String name;
    int age;
    //2.定义构造方法
    //空构造方法，标配
    public Person(){   }
    //初始化所有数据成员的构造方法
    public Person (String aName,  int aAge){
        name = aName;
        age = aAge;
    }
    //3.定义成员方法
    public void writing (Pen pen,String msg){
        System.out.println(name + "写");
        pen.show(msg);
    }
}
public class Demo {
    public static void main(String[] args) {
        Person shk = new Person("沈括",56);
        shk.writing(new Pen(), "梦溪笔谈");    //创建没有对象名的Pen对象
        //或者如下代码
        //Pen aPen = new Pen();         //命名对象，对象名aPen
        //shk.writing(aPen,"梦溪笔谈“);
    }
}