[dotnet] Add dotnet projects and examples

+ Sitemap generator I created while learning the dispose pattern
+ Testing project for learning general C#

dotnet/testing/KlipsLibrary/Shape.cs

@@ -0,0 +1,98 @@
+namespace KlipsLibrary;
+
+public class Shape
+{
+  public Shape(int y, int x)
+  {
+    Y = y;
+    X = x;
+    Name = this.ToString();
+  }
+
+  public Shape()
+  {
+    X = 0;
+    Y = 0;
+    Name = this.ToString();
+  }
+
+  // Shape position; Private setter, public getter
+  public int X { get; private set; }
+  public int Y { get; private set; }
+  public string Name { get; private set; }
+  
+  // Auto-implemented properties may use a default value initializer
+  public virtual int Width { get; set; } = 1;
+  public virtual int Height { get; set; } = 2;
+  
+  public virtual void Print()
+  {
+    Console.WriteLine($"{Name} WxH is {Width}x{Height} at position ({X},{Y})");
+  }
+}
+
+public class Square : Shape
+{
+  // Set default value on encapsulated value for non auto-implemented properties
+  private int width = 10;
+  private int height = 10;
+
+  // We can override properties just as we can functions
+  // + Height and Width properties can no longer set default values
+  public override int Height
+  {
+    // Can use expressions for getters / setters
+    get => height;
+    set => width = height = value;
+  }
+
+  public override int Width
+  {
+    get => width;
+    set
+    {
+      // Same setter as Height, just within a block of statements
+      width = value;
+      height = value;
+    }
+  }
+
+  public override void Print()
+  {
+    Console.WriteLine("Printing Square info...");
+    base.Print(); // Will use Square's getter / setter to print private int width, height
+  }
+}
+
+public class Cube : Square
+{
+  // Add new properties or encapsulated values as needed
+  private int depth = 10;
+  public int Depth
+  {
+    get => depth;
+    set => depth = value;
+  }
+  // Implement a `new` Print() function which acts as a new stand-alone implementaton 
+  public new void Print()
+  {
+    Console.WriteLine("Printing Cube info...");
+    Console.WriteLine($"{Name} WxHxD is {Width}x{Height}x{Depth} at position ({X},{Y})");
+  }
+}
+
+public class Rectangle : Shape
+{
+  // Classes that inherit from Rectangle can not override Print
+  public sealed override void Print()
+  {
+    Console.WriteLine("Printing sealed Rectangle info...");
+    base.Print();
+  }
+}
+
+public class Rect : Rectangle
+{
+  // Rect can't override Print(), since its base class declared it as `sealed`
+}
+