C#

Using System.Collections.Generic;
[...].
List<Byte>myList = new List<Byte>();

//Add range from some byte array:
myList.AddRange(someByteArray);

//Remove first 16 bytes:
myList.RemoveRange(0,16);

//Append some other array:
myList.AddRange(someOtherByteArray);

//Finally, get an array representation of this list:
Byte[] retVal = myList.ToArray();

return retVal;

indian143 wrote:

Whats the use in writing it.

{;};

public class Class
{
    private string name;

    public Class(string name)
    {
        this.name = name;
    }
    public Class()
        : this(string.Empty)
    { }

    public string Name
    {
        get { return name; }
    }
}

public double PolygonArea2
       {
           get{
               //check: at least 3 points.

               #region invariant check
               if (size < 3)
               {
                   throw new Exception("Cannot compute area, \"Polygon\" does not have at least 3 points");
               }
               #endregion

               if (currAreaValid)
               {
                   return area;
               }
               //else:

               //iterative method: sum point triplets as signed areas...set to area
               area = (Double)(Fold(area2FoldHelper, (Object)(new Double()), this[0]).First);
               currAreaValid = true;
               return area;
           }
       }

       private static Tuple<Object, Point> area2FoldHelper(Point currentPoint, Object totalArea, Point bound)
       {

           //increase the current area by the next triplet of points' area:
           if (currentPoint.Next.Next == bound || currentPoint.Next == bound.Next)
           {
               return new Tuple<Object, Point>(totalArea, bound);
           }

           Double areaToAdd = ((Double)totalArea) + Globals.Area2(currentPoint, currentPoint.Next, currentPoint.Next.Next);
           return new Tuple<Object, Point>((Object)areaToAdd, bound);
       }

  public Tuple<Object, Point> Fold(FoldDelegate fdel, Object initObjVal, Point initPoint)
       {
           Tuple<Object, Point> tuple = new Tuple<Object, Point>(initObjVal, initPoint);

           for (int i = 0; i < size; i++)
           {
               tuple = fdel(vertices, tuple.First, tuple.Second);
               vertices = vertices.Next;
           }

           return tuple;
       }

//gets twice the signed area of a triangle
      public static double Area2(Point a, Point b, Point c)
      {
          return (b.Coords[X] - a.Coords[X]) * (c.Coords[Y] - a.Coords[Y]) -
                 (c.Coords[X] - a.Coords[X]) * (b.Coords[Y] - a.Coords[Y]);
      }

aespielberg wrote:

I normally do go step by step, but with this error (which seems so bizarre), other than the delegates, I really didn't know what to check...

aespielberg wrote:

so I guess delegates use threading after all

class Polygon: Polytope

class Polytope

private bool currAreaValid;
private double area;

protected int size;

public static void log(string s) {
    s=DateTime.Now.ToString("HH:mm:ss.fff")+
        " ["+Thread.GetCurrentThread().ManagedThreadID.ToString("X2")+"] "+s;
    Console.WriteLine(s);
    // optional:
    // Console.WriteLine(Environment.StackTrace);
}

log("start");

log("area="+area+"  currAreaValid="+currAreaValid);

aespielberg wrote:

public double PolygonArea2
{
get{...
currAreaValid = true;
}
}