Algorithm

 1  char[] cha = { ‘A‘, ‘ ‘, ‘B‘, ‘ ‘, ‘ ‘, ‘C‘, ‘ ‘, ‘a‘, ‘ ‘, ‘ ‘, ‘ ‘, ‘b‘, ‘ ‘, ‘c‘, ‘ ‘, ‘f‘, ‘g‘, ‘1‘, ‘2‘, ‘ ‘, ‘3‘, ‘4‘, ‘5‘, ‘ ‘, ‘6‘ };
 2             for (int i = 0; i < cha.Length; i++)
 3             {
 4                             if (cha[i].ToString() == " ")
 5                             {
 6                                             for (int j = i; j < cha.Length - i; j++)
 7                                             {
 8                                                             //if (cha[j].ToString() == " ")
 9                                                             //{
10                                                                             cha[j] = cha[j + 1];
11                                                                             //cha[j + 1] = ‘ ‘;
12                                                             //}
13                                             }
14                                             //string charTemp = cha.ToString();// new string(cha);
15                                             //Console.WriteLine(charTemp);
16                             }
17             }
18             string str = new string(cha);
19             Console.Write(str);//AB Ca bcfg123345      666
20             Console.ReadKey();