//寄送報紙
public void SendNewspaper(Newspaper newspaper)
{
newspaper.Name = this.Name;
/*
* //此寫法代碼不封閉，雖然報紙寄送給Person，但對於閱讀報紙，
* //在程式執行時還要再建立一次Pereson物件，變成接收和閱讀的Person是不同的物件
* Person p1 = new Person("p1");
* Person p2 = new Person("p2");
* Person p3 = new Person("p3");
*
* p1.ReceiveNewspaper(newspaper);
* p2.ReceiveNewspaper(newspaper);
* p3.ReceiveNewspaper(newspaper);
*/
// 使用委託，由程式執行時創建Person物件決定寄送報紙對象
//persons.ForEach(delegate (Person p) { p.ReceiveNewspaper(newspaper); });
persons.ForEach(p => p.ReceiveNewspaper(newspaper));
companies.ForEach(c => c.ReceiveNewspaper(newspaper));
//面向接口編程(觀察者模式又稱訂閱發布模式):將公共操作統一到接口
//此時因為又增加對象，變成代碼不封閉，於是讓訂報者實現有接收報紙方法的介面
Subscribers.ForEach(objs => objs.ReceiveNewspaper(newspaper));
}
//接收報紙
public void ReceiveNewspaper(Newspaper newspaper)
{
this.Newspaper = newspaper;
}