static void Main(string[] args)
        {
            //用stringreader读取字符串的值并显示
            // Create a string to read characters from.
            String str = "Some number of characters";
            // Size the array to hold all the characters of the string
            // so that they are all accessible.
            char[] b = new char[24];
            // Create an instance of StringReader and attach it to the string.
            StringReader sr1 = new StringReader(str);
            sr1.Read(b, 0, str.Length - 1);
            // sr.Read(b, 0, 13);

            // Display the output.
            //console.writeline(char[]);输出字符数组的值
            Console.WriteLine(b);
            // Close the StringReader.
            sr1.Close();
            Console.ReadKey();

            

            //用stringwriter（通过stringbuilder)向字符串中写入字符
            StringBuilder sb = new StringBuilder("可变字符串　测试　难");
            char[] c ={ ' ','t','c','s','b','.'};
            StringWriter sw = new StringWriter(sb);
            sw.Write(c,0,c.Length-1);
            sw.Close();

            Console.WriteLine(sb);
            Console.ReadKey();
        }