详细介绍C#实例化接口对象的方法

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{

  interface Itemp

  {

    double plus();

  }

  public class num : Itemp

  {

    double aa, bb;

    public num(double a, double b)

    {

      this.bb = b;

      this.aa = a;

    }

    public double plus()

    {

      return (aa * bb);

    }

  }

  class Program

  {

    static void Main(string[] args)

    {

      num n = null;//声明类对象引用

      Itemp tm = null;//声明接口对象引用

      tm = new num(1.1, 2.2);//接口回调(向上转型)

      Console.WriteLine(tm.plus());

      Console.ReadKey();

    }

  }

}