C#封装内部访问修饰符

using System;

namespace RectangleApplication {

   class Rectangle {
      //member variables
      internal double length;
      internal double wIDth;

      double GetArea() {
         return length * wIDth;
      }

      public voID display() {
         Console.Writeline("Length: {0}", length);
         Console.Writeline("WIDth: {0}", wIDth);
         Console.Writeline("Area: {0}", GetArea());
      }
   }//end class Rectangle

   class ExecuteRectangle {
      static voID Main(string[] args) {
         Rectangle r = new Rectangle();
         r.length = 4.5;
         r.wIDth = 3.5;
         r.display();
         Console.Readline();
      }
   }
}