第一章 简单工厂模式\计算器

     今天重新把昨天看的《大话设计模式》第一章温习了一边，发现很多都没搞懂，做不出来。废话少说上代码：

//OperationLibrary

public class Operation
    {
        private double _numberA = 0;
        private double _numberB = 0;

        /**//// <summary>
        /// 数字A
        /// </summary>
        public double NumberA
        {
            get
            {
                return _numberA;
            }
            set
            {
                _numberA = value;
            }
        }

        /**//// <summary>
        /// 数字B
        /// </summary>
        public double NumberB
        {
            get
            {
                return _numberB;
            }
            set
            {
                _numberB = value;
            }
        }

        /**//// <summary>
        /// 得到运算结果
        /// </summary>
        /// <returns></returns>
        public virtual double GetResult()
        {
            double result = 0;
            return result;
        }

        /**//// <summary>
        /// 检查输入的字符串是否准确
        /// </summary>
        /// <param name="currentNumber"></param>
        /// <param name="inputString"></param>
        /// <returns></returns>
        public static string checkNumberInput(string currentNumber, string inputString)
        {
            string result = "";
            if (inputString == ".")
            {
                if (currentNumber.IndexOf(".") < 0)
                {
                    if (currentNumber.Length == 0)
                        result = "0" + inputString;
                    else
                        result = currentNumber + inputString;
                }
                else
                {
                    result = currentNumber;
                    System.Media.SystemSounds.Beep.Play();
                }
            }
            else if (currentNumber == "0")
            {
                result = inputString;
            }
            else
            {
                result = currentNumber + inputString;
            }

            return result;
        }


    }

    /**//// <summary>
    /// 加法类
    /// </summary>
    class OperationAdd : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA + NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 减法类
    /// </summary>
    class OperationSub : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA - NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 乘法类
    /// </summary>
    class OperationMul : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA * NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 除法类
    /// </summary>
    class OperationDiv : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            if (NumberB == 0)
                throw new Exception("除数不能为0。");
            result = NumberA / NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 平方类
    /// </summary>
    class OperationSqr : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberB * NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 平方根类
    /// </summary>
    class OperationSqrt : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            if (NumberB < 0)
                throw new Exception("负数不能开平方根。");
            result = Math.Sqrt(NumberB);
            return result;
        }
    }

    /**//// <summary>
    /// 相反数类
    /// </summary>
    class OperationReverse : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = -NumberB;
            return result;
        }
    }

    /**//// <summary>
    /// 运算类工厂
    /// </summary>
public class OperationFactory
{
    public static Operation createOperate(string operate)
    {
        Operation oper = null;
        switch (operate)
        {
            case "+":
                {
                    oper = new OperationAdd();
                    break;
                }
            case "-":
                {
                    oper = new OperationSub();
                    break;
                }
            case "*":
                {
                    oper = new OperationMul();
                    break;
                }
            case "/":
                {
                    oper = new OperationDiv();
                    break;
                }
            case "sqr":
                {
                    oper = new OperationSqr();
                    break;
                }
            case "sqrt":
                {
                    oper = new OperationSqrt();
                    break;
                }
            case "+/-":
                {
                    oper = new OperationReverse();
                    break;
                }
        }

        return oper;
    }
}

//计算器控制台

class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Console.Write("请输入数字A：");
                string strNumberA = Console.ReadLine();
                Console.Write("请选择运算符号(+、-、*、/)：");
                string strOperate = Console.ReadLine();
                Console.Write("请输入数字B：");
                string strNumberB = Console.ReadLine();
                string strResult = "";

                Operation oper;
                oper = OperationFactory.createOperate(strOperate);
                oper.NumberA = Convert.ToDouble(strNumberA);
                oper.NumberB = Convert.ToDouble(strNumberB);
                strResult = oper.GetResult().ToString();

                Console.WriteLine("结果是：" + strResult);

                Console.ReadLine();


            }
            catch (Exception ex)
            {
                Console.WriteLine("您的输入有错：" + ex.Message);
            }
        }
    }

在实际操作
中，出现了几个问题，比如OperationLibrary中空间命名OperationLibrary要引用到计算器控制台中，我搞了半天才知道，要用到CSC命令讲Operation.cs转为Operation.dll，而CSC命令在vs2005具体哪个位置，我现在都没有找到。郁闷啊!
我不知道怎么调用项目OperationLibrary将Main接入口转移到计算器控制台program里来——通过CSC命令：CSC Operation.cs Program.cs Main:Program，结果怎么也不对，显示找不到Main中Program。
除了这些，我还搞不清楚在计算器项目中ClassDiagram1.cd的MUL是怎么查看的或者怎么生成？

请高手解答一下。谢谢