#include <iostream>using namespace std;

// 1、声明typedef void (*PF)();// 2、定义void func(){  cout << "func" << endl;}

void caller( PF pf){  pf();}

int main(){  PF p = func;  // 3、函数作为参数传递  caller(p);

  system("pause");

  return 0;}

using System;using System.Runtime.InteropServices;// 1、函数声明public delegate bool CallBack(int hwnd, int lParam);

public class EnumReportApp{    [DllImport("user32")]    public static extern int EnumWindows(CallBack x, int y); 

    public static void Main()     {        // 3、函数作为参数传递        CallBack myCallBack = new CallBack(EnumReportApp.Report);        EnumWindows(myCallBack, 0);    }    // 2、函数定义    public static bool Report(int hwnd, int lParam)    {         Console.Write("Window handle is ");        Console.WriteLine(hwnd);        return true;    }}

public interface GasListener{    public void offerGas(String msg);}

接口实现的甲方：

public class GasCompany implements GasListener{        public void advertiseTo(IndoorsMan man)    {        System.out.println("煤气公司：这是我们的联系方式，欢迎来电！");        man.setListener(this);    }    @Override    public void offerGas(String msg)    {        System.out.println("煤气公司接收的订单："+msg);    }}

调用者：

public class IndoorsMan {    GasListener gListener;    public void prepareCook()    {        System.out.println("宅男：准备下厨做几个花式大菜！");        System.out.println("宅男：进厨房，烧菜...");        System.out.println("宅男：刚开火，就发现煤气不足，没办法，只能打电话叫煤气。");        gListener.offerGas("宅男：送一瓶煤气过来!");    }        public void setListener(GasListener gListener)    {        this.gListener = gListener;    }}

测试：

public class Test{    public static void main(String[] args)    {        IndoorsMan man = new IndoorsMan();        GasCompany company = new GasCompany();

        company.advertiseTo(man);        man.prepareCook();    }            }

GasCompany公司在打广告时，就主动把自身信息告诉了IndoorsMan，当IndoorsMan发现煤气不足这一事件发生时，IndoorsMan就根据接口的引用调用GasCompany服务。

public class IndoorsMan {    GasListener gListener;    public void prepareCook()    {        System.out.println("宅男：准备下厨做几个花式大菜！");        System.out.println("宅男：进厨房，烧菜...");        System.out.println("宅男：刚开火，就发现煤气不足，没办法，只能打电话叫煤气。");        gListener.offerGas("宅男：送一瓶煤气过来!");    }        public void setListener(GasListener gListener)    {        this.gListener = gListener;    }    public void configureGas()    {        // 主动获取甲方信息        setListener(new GasListener()        {                        @Override            public void offerGas(String msg)            {                System.out.println("下单内容："+msg);            }        });    }    }

public class Test{    public static void main(String[] args)    {        IndoorsMan man = new IndoorsMan();        man.configureGas();        man.prepareCook();    }            }

public class Test{    public static void main(String[] args)    {        Thread thread = new Thread(new Runnable()        {            @Override            public void run()            {

            }        });    }            }