using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace 工厂方法实现计算器
{
  /// <summary>
  /// 计算器类（抽象类，由子类重写）
  /// </summary>
  public abstract class Calculator
  {
    public double Number1 { get; set; }
    public double Number2 { get; set; }
    public Calculator() { }
    public Calculator(double a, double b)
    {
      this.Number1=a;
      this.Number2=b;
    }
    /// <summary>
    /// 计算
    /// </summary>
    /// <returns></returns>
    public abstract double jsuan();
  }
  /// <summary>
  /// 加法类
  /// </summary>
  public class jiafaDll:Calculator //子类拥有父类除私有之外的所有属性字段和方法
  {
    public jiafaDll() { }
    public jiafaDll(double a, double b)
      : base(a, b)  //调用父类带两个参数的构造函数，来初始化Number1 和Number2 （注意：因为jianfaDll类继承了Calculator，所以jianfaDll类是有Number1，和Number2两个属性的）
    { }
    /// <summary>
    /// 重写父类的jsuan方法
    /// </summary>
    /// <returns></returns>
    public override double jsuan()
    {
      return Number1 + Number2;
    }
  }
  /// <summary>
  /// 减法类
  /// </summary>
  public class jianfaDll : Calculator
  {
    public jianfaDll()
    { }
    public jianfaDll(double a, double b)
      : base(a, b)
    { }
    public override double jsuan()
    {
      return Number1 - Number2;
    }
  }
  class Program
  {
    static void Main(string[] args)
    {
      Console.WriteLine("请输入第一个数");
      double number1 = Convert.ToDouble(Console.ReadLine());
      Console.WriteLine("请输入一个操作符");
      string caozuofu = Console.ReadLine();
      Console.WriteLine("请输入第二个数");
      double number2 = Convert.ToDouble(Console.ReadLine());
      Calculator c=null;
      switch (caozuofu)
      {
        case "+":
          c = new jiafaDll(number1, number2);
          break;
        case "-":
          c = new jianfaDll(number1, number2);
          break;
      }
      double i= c.jsuan();
      Console.WriteLine(i);
      Console.ReadKey();
    }
  }
}