using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

//如果账户金额小于0 触发事件

namespace Starter

{

    public enum Comparison

    {

        theFirstComesFirst = 1,

        theSecondComesFirst = 2

    }

    //包含两项的简单集合

    public class Pair<T>

    {

        //存放两个对象的私有数组

        private T[] thePair = new T[2];

        //委托声明

        public delegate Comparison WhichIsFirst(T obj1, T obj2);

        //构造方法，参数为两个对象，按接收顺序添加

        public Pair(T firstObject, T secondObject)

        {

            thePair[0] = firstObject;

            thePair[1] = secondObject;

        }

        //公共方法，按对象具体顺序范畴排序

        public void Sort(WhichIsFirst theDelegatedFunc)

        {

            if (theDelegatedFunc(thePair[0], thePair[1]) == Comparison.theSecondComesFirst)

            {

                T temp = thePair[0];

                thePair[0] = thePair[1];

                thePair[1] = temp;

            }

        }

        //反序排列

        public void ReverSort(WhichIsFirst theDelegatedFunc)

        {

            if (theDelegatedFunc(thePair[0], thePair[1]) == Comparison.theFirstComesFirst)

            {

                T temp = thePair[0];

                thePair[0] = thePair[1];

                thePair[1] = temp;

            }

        }

        //要求两个对象提供字符串值

        public override string ToString()

        {

            return thePair[0].ToString() + ", " + thePair[1].ToString();

        }

    }

    public class Dog

    {

        private int weight;

        public Dog(int weight)

        {

            this.weight = weight;

        }

        public static Comparison WhichDogComesFirst(Dog d1,Dog d2)

        {

            return d1.weight > d2.weight ?

                Comparison.theSecondComesFirst : Comparison.theFirstComesFirst;

        }

        public override string ToString()

        {

            return weight.ToString();

        }

    }

    public class Student

    {

        private string name;

        public Student(string name)

        {

            this.name = name;

        }

        public static Comparison WhichStudentComesFirst(Student s1, Student s2)

        {

            return (String.Compare(s1.name, s2.name)<0 ?

                Comparison.theFirstComesFirst : Comparison.theSecondComesFirst

                );

        }

        public override string ToString()

        {

            return name;

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            Student Jess = new Student("Jess");

            Student Mary = new Student("Mary");

            Dog Milo = new Dog(26);

            Dog Free = new Dog(12);

            Pair<Student> studentPair = new Pair<Student>(Jess,Mary);

            Pair<Dog> dogPair = new Pair<Dog>(Milo, Free);

            Console.WriteLine("student pair: " + studentPair.ToString());

            Console.WriteLine("dog pair: " + dogPair.ToString());

            //Pair下的委托函数 new 出来，Student下的WhichStudentComesFirst绑定到委托函数，参数列表需要相同

            Pair<Student>.WhichIsFirst theStudentDelegate = new Pair<Student>.WhichIsFirst(Student.WhichStudentComesFirst);

            Pair<Dog>.WhichIsFirst theDogDelegate = new Pair<Dog>.WhichIsFirst(Dog.WhichDogComesFirst);

            studentPair.Sort(theStudentDelegate);

            Console.WriteLine("student after sort: " + studentPair.ToString());

            studentPair.ReverSort(theStudentDelegate);

            Console.WriteLine("student after ReverSort: " + studentPair.ToString());

            Console.ReadLine();

        }

    }

}