C#封装public访问修饰符

namespace RectangleApplication {

   class Rectangle {
      //member variables
      public double length;
      public double width;

      public 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();
      }
   }
}