Quelle est la portée des variables membres publiques d'une classe en C# ?

Rectangle r = new Rectangle();
r.length = 4.5;
r.width = 3.5;

Using System;
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();
      }
   }
}