C#字符串(Sring)操作

 

            //StringBuilder stringBuilder = new StringBuilder();//一种很高效的连接字符串的方式
            //stringBuilder.Append(arr[0]);
            //stringBuilder.Append(arr[1]);
            //stringBuilder.Append(arr[2]);
            //stringBuilder.Append(arr[3]);
            //Console.WriteLine(stringBuilder.ToString());