如何正确编写getAlpha方法

Question

我试图找到一种方法来玩“ longestword”游戏，由于二进制排序树，我基本上从输入文件到输出文件的字母数组中提取单词。我在下面找到了一个看起来还不错的小程序。

但是我遇到了方法“ getAlpha”的问题，据说该方法在特殊情况下使用，因为它会在读取前跳过所有非字母，而不仅仅是跳过空白字符。在程序中没有提到它，我现在也不怎么写它了。

// ------------------主程序------------------------ ------------

  static TreeNode root;  // Points to the root of the binary sort
                         //   tree that holds the words.  At the
                         //   beginning of the program, when the tree
                         //   is empty, root is null.


  public static void main(String[] args) {

     TextReader in;    // A stream for reading from the input file.
     PrintWriter out;  // A stream for writing to the output file.

     String inputFileName;   // Input file name, specified by the user.
     String outputFileName;  // Output file name, specified by the user.

     root = null;  // Start with an empty tree.  (Not really necessary,
                   //   since null is the default initial value anyway.)

     /* Get the input file name from the user and try to create the
        input stream.  If there is a FileNotFoundException, print
        a message and terminate the program. */

     TextIO.put("Input file name?  ");
     inputFileName = TextIO.getln().trim();
     try {
        in = new TextReader(new FileReader(inputFileName));
     }
     catch (FileNotFoundException e) {
         TextIO.putln("Can't find file \"" + inputFileName + "\".");
         return;
     }

     /* Get the output file name from the user and try to create the
        output stream.  If there is an IOException, print a message
        and terminate the program. */

     TextIO.put("Output file name? ");
     outputFileName = TextIO.getln().trim();
     try {
        out = new PrintWriter(new FileWriter(outputFileName));
     }
     catch (IOException e) {
         TextIO.putln("Can't open file \"" + outputFileName + "\" for output.");
         TextIO.putln(e.toString());
         return;
     }

     /* Read all the words from the input stream and insert them into
        the array of words.  Reading from a TextReader can result in
        an error of type TextReader.Error.  If one occurs, print an
        error message and terminate the program. */

     try {
        while (true) {
              // Skip past and non-letters in the input stream.  If an
              //   end-of-stream has been reached, end the loop.  Otherwise,
              //   read a word and insert it into the array of words.
           while ( ! in.eof() && ! Character.isLetter(in.peek()) )
              in.getAnyChar();
           if (in.eof())
              break;
           insertWord(in.getAlpha());        `**the required method**`
        }
     }
     catch (TextReader.Error e) {
        TextIO.putln("An error occurred while reading from the input file.");
        TextIO.putln(e.toString());
        return;
     }