using System;
using System.Collections.Generic;
namespace Test{
  class A{
    public delegate void Callback();
    private List<Callback> ls = new List<Callback>();
    public void AddCallBack(Callback c){ls.Add(c);}
    public void Call(){foreach(var c in ls){c();}}
  }
  class Test{
    public static void f1(){
      Console.WriteLine("f1");
    }
    public static void f2(int n){
      Console.WriteLine("f2:"+n);
    }
    public static void Main(string[] args){
      A a = new A();
      a.AddCallBack(delegate(){f1();});
      a.AddCallBack(delegate(){f2(100);});
      a.Call();
    }
  }
}