using System.Globalization;
public static void Main()
DateTime x = new DateTime(2015,12,31);
int i1 = getWeekOfYearIso8601(x);
DateTime y = new DateTime(2016,1,1);
int i2 = getWeekOfYearIso8601(y);
Console.WriteLine(x.Year);
Console.WriteLine(y.Year);
string[] ua = u.Trim().Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);