Java.io.StreamTokenizer.slashSlashComments() Method

Description

The java.io.StreamTokenizer.slashSlashComments(boolean flag) method determines whether or not the tokenizer recognizes C++-style comments. If the flag argument is true, this stream tokenizer recognizes C++-style comments. Any occurrence of two consecutive slash characters ('/') is treated as the beginning of a comment that extends to the end of the line. If the flag argument is false, then C++-style comments are not treated specially.

Declaration

Following is the declaration for java.io.StreamTokenizer.slashSlashComments() method

public void slashSlashComments(boolean flag)

Parameters

• flag -- true indicates to recognize and ignore C++-style comments.

Return Value

This method does not return a value

Exception

• NA

Example

The following example shows the usage of java.io.StreamTokenizer.slashSlashComments() method.

package com.tutorialspoint;

import java.io.*;

public class StreamTokenizerDemo {
   
   public static void main(String[] args) {
      
      String text = "Hello. This is a text \n that //will be split "
              + "into tokens. 1+1=2";
      try {
         // create a new file with an ObjectOutputStream
         FileOutputStream out = new FileOutputStream("test.txt");
         ObjectOutputStream oout = new ObjectOutputStream(out);

         // write something in the file
         oout.writeUTF(text);
         oout.flush();

         // create an ObjectInputStream for the file we created before
         ObjectInputStream ois =
                 new ObjectInputStream(new FileInputStream("test.txt"));

         // create a new tokenizer
         Reader r = new BufferedReader(new InputStreamReader(ois));
         StreamTokenizer st = new StreamTokenizer(r);

         // set slash-slash comments as recognizable
         st.slashSlashComments(true);

         // print the stream tokens
         boolean eof = false;
         do {
            
            int token = st.nextToken();
            
            switch (token) {
               case StreamTokenizer.TT_EOF:
                  System.out.println("End of File encountered.");
                  eof = true;
                  break;
               case StreamTokenizer.TT_EOL:
                  System.out.println("End of Line encountered.");
                  break;
               case StreamTokenizer.TT_WORD:
                  System.out.println("Word: " + st.sval);
                  break;
               case StreamTokenizer.TT_NUMBER:
                  System.out.println("Number: " + st.nval);
                  break;
               default:
                  
                  System.out.println((char) token + " encountered.");
                  if (token == '!') {
                     eof = true;
                  }
            }
            
         } while (!eof);
         
         
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

Let us compile and run the above program, this will produce the following result:

Word: Hello.
Word: This
Word: is
Word: a
Word: text
Word: that
End of File encountered.