1、简单工厂模式

一、做一个商场收银软件

二、Code

using System; 

namespace Web.策略模式
{
    
        /// <summary>
        /// 现金收费抽象类
        /// </summary>
        public abstract class CashSuper
        {
            /// <summary>
            /// 现金收取超类的抽象方法，收取现金，参数为原价，返回当前价
            /// </summary>
            /// <param name="money"></param>
            /// <returns></returns>
            public abstract double AcceptCash(double money);
        }

        /// <summary>
        /// 正常收费子类
        /// </summary>
        class CashNoraml:CashSuper
        {
            /// <summary>
            /// 正常收费 返回价格
            /// </summary>
            /// <param name="money"></param>
            /// <returns></returns>
            public override double AcceptCash(double money)
            {
                return money;
            }
        }

        /// <summary>
        /// 打折收费子类
        /// </summary>
        public  class CashRebate : CashSuper
        {
            private double moneyRebate = 1d;

            public CashRebate(string moneyRebate)
            {
                this.moneyRebate = double.Parse(moneyRebate);
            }
            /// <summary>
            /// 返回折扣价格×原价
            /// </summary>
            /// <param name="money"></param>
            /// <returns></returns>
            public override double AcceptCash(double money)
            {
                return money*moneyRebate;
            }
        }
        /// <summary>
        /// 返利收费子类
        /// </summary>
        public class CashReturn : CashSuper
        {
            private double moneyCondition = 0.0d;
            private double moneyRetrun = 0.0d;
            /// <summary>
            /// 返利收费，
            /// 初始化时必须要输入返利条件和返回值，比如满300返100，则moneyCondition为300，momeyReturn为100
            /// </summary>
            /// <param name="moneyCondition"></param>
            /// <param name="moneyReturn"></param>
            public CashReturn(string moneyCondition, string moneyReturn)
            {
                this.moneyCondition =double.Parse(moneyCondition) ;
                this.moneyRetrun =double.Parse(moneyReturn) ;
            }
            /// <summary>
            ///若大于返利条件则需要减去返利值
            /// </summary>
            /// <param name="money"></param>
            /// <returns></returns>
            public override double AcceptCash(double money)
            {
                double result = money;
                if (money>moneyCondition)
                {
                    result = money - Math.Floor(money/moneyCondition)*moneyRetrun;
                }
                return result;  
            }
        }
        /// <summary>
        /// 现金收费工厂类
        /// </summary>
        public class CashFactory
        {
            public static CashSuper CreateCashSuper(string type)
            {
                CashSuper cash = null;
                switch (type)
                {
                    case "正常收费":
                    cash=new CashNoraml();
                        break;
                    case "满300返100":
                    cash =new CashReturn("300","100");
                        break;
                    case "打折：85折":
                        cash=new CashRebate("0.85");
                        break;
                }
                return cash;
            }
        }

    /// <summary>
    /// 客户端实现
    /// </summary>
    class Customer
    {
        public void Method()
        {
             CashSuper cash = CashFactory.CreateCashSuper("type");
             cash.AcceptCash(100);
        } 
    }
}