struct and enum

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Text;
 4 
 5 namespace struck
 6 {
 7     public enum color { red,green,blue,white,black}
 8     public struct Mypoint
 9     {
         public int x;
       
         public int y;
         public Mypoint(int point_x,int point_y)
         {
             this.x = point_x+point_y;
            
             this.y = point_y-point_x;
         }
 
         public static Mypoint operator +(Mypoint p1, Mypoint p2)
         { 
             return new Mypoint (p1.x +p2.x ,p1.y +p2.y );
         }
     
     }
     class Mypoint1
     {
         public int x=10;
         public int y=16;
 
         static void Main(string[] args)
         {
             Mypoint p = new Mypoint(20, 19);
             Mypoint p2 = new Mypoint(100,30);
             Mypoint p3 = new Mypoint();
             p3 = p + p2;
             Mypoint1 p1 = new Mypoint1();
             p1.x = 19;
             Console.WriteLine(p3.x+","+p3.y);//输出：98 240 这个等于先等于（130+39，69）然后（169-71，-71-169）
             Console.WriteLine(p2.x + "," + p2.y);//130,-70
            
             Console.WriteLine(p.x+","+p.y);//39,-1
 
             Console.WriteLine(color.green);//输出green 实际上是个数字,另外枚举没有要实例化
             Console.WriteLine(Convert.ToInt32(color.green));//1
             Console.ReadLine();
         }
     }
 }