ToUpperInvariant and Array.Sort

           string[] words = { "Tuesday", "Sal?", "Вторник", "Mardi", 
                         "Τρ?τη", "Martes", "??? ?????", 
                         "????????", "?????????" };
                      StreamWriter sw = new StreamWriter(@".\output.txt");

                      // Display array in unsorted order.
                      foreach (string word in words)
                            sw.WriteLine(word);

                      sw.WriteLine();

                      // Create parallel array of words by calling ToUpperInvariant.
                      string[] upperWords = new string[words.Length];
                      for (int ctr = words.GetLowerBound(0); ctr <= words.GetUpperBound(0); ctr++)
                            upperWords[ctr] = words[ctr].ToUpperInvariant();

                      // Sort the words array based on the order of upperWords.
                      Array.Sort(upperWords, words, StringComparer.InvariantCulture);

                      // Display the sorted array.
                      foreach (string word in words)
                            sw.WriteLine(word);

                      sw.Close();