using System;

public class Program

{

    public static void Main()

    {

        string x = "|Hello World";

        Console.WriteLine(GetDrawingAnnotationThickness(x)?.ToString() ?? "NULL");

        SetDrawingAnnotationThickness(ref x, 5);

        Console.WriteLine(x);

    }

     private static double? GetDrawingAnnotationThickness(string annotationPoints)

        {

            //if and only if the annotation type is drawing

            if (true)

            {

                if (!string.IsNullOrEmpty(annotationPoints))

                {

                    //get the first string part befor the colon (:)

                    string annotationThickness = annotationPoints.Substring(0, annotationPoints.IndexOf('|'));

​

                    //check if the first part is normal point or the thickness

                    if (string.IsNullOrEmpty(annotationThickness))

                    {

                        return null;

                    }

​

                    return Convert.ToInt64(annotationThickness);

                }

            }

​

            return null;

        }

    private static void SetDrawingAnnotationThickness(ref string annotationPoints, double? annotationDrawingThickness)

        {

            //if and only if the annotation type is drawing

            if (true)

            {

                if (annotationDrawingThickness != null && !string.IsNullOrEmpty(annotationPoints))

                {

                    int annotationThicknessMarkIndex = annotationPoints.IndexOf('|');

​

                    //if the annotation is already contain thickness, so, let us remove it, to be updated with the latest thickness

                    if (annotationThicknessMarkIndex > 0)

                    {

                        //remove the old thickness along with the thickness mark, which is the bar sign ( | )

                        annotationPoints = annotationPoints.Remove(0, annotationThicknessMarkIndex + 1);

                    }

​

                    annotationPoints = annotationDrawingThickness.ToString() + "|" + annotationPoints;

                }

            }

        }

​

}