设计模式--策略模式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace StrategySample
{
    class Program
    {
        static void Main(string[] args)
        {
            Ticket mticket = new Ticket(100);
            Console.WriteLine("当前价格" + mticket.Price);
            Discount mdis=  new StudentDiscount();
            mticket.SetDiscount(mdis);
            Console.WriteLine("当前价格" + mticket.Price);
            Console.Read();

        }
    }
    class Ticket
    {
        private double price;
        private Discount discount;
        public Ticket(double price)
        { this.price = price; }
        public void SetDiscount(Discount discount)
        {
            this.discount = discount;
        }
        public double Price
        {
            get {if (discount != null)
                    return discount.Caculate(this.price);
                else
                    return this.price;
            }
            set { price = value; }
        }

    }
    interface Discount
    {
        double Caculate(double price);
    }
    class StudentDiscount:Discount
    {
        private const double DISCOUNT = 0.5;
        public double Caculate(double price)
        {
            Console.WriteLine("学生票");
            return price * DISCOUNT;
        }
    }
    class VIPDiscount : Discount
    {
        private const double DISCOUNT = 0.8;
        public double Caculate(double price)
        {
            Console.WriteLine("VIP票");
            return price * DISCOUNT;
        }
    }
}