C#图解 - 扩展方法

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

namespace ConsoleApplication1
{
    sealed class MyData
    {
        private double d1, d2, d3;

        public MyData(double d1, double d2, double d3)
        {
            this.d1 = d1;
            this.d2 = d2;
            this.d3 = d3;
        }

        public double Sum()
        {
            return d1 + d2 + d3;
        }
    }

    static class ExtendMyData
    {
        public static double Agerage(this MyData md, int count)
        {
            Console.WriteLine(count);

            return md.Sum() / count;
        }
    }
    
    class Program
    {
        static void Main(string[] args)
        {
            MyData md = new MyData(6d,5d,9d);
            md.Agerage(3);

            Console.ReadKey();
        }
    }
}

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