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Java StreamTokenizer slashStarComments() Method with Example

StreamTokenizer Class slashStarComments() method: Here, we are going to learn about the slashStarComments() method of StreamTokenizer Class with its syntax and example.
Submitted by Preeti Jain, on April 23, 2020

StreamTokenizer Class slashStarComments() method

• slashStarComments() method is available in java.io package.
• slashStarComments() method is used to identify whether this StreamTokenizer recognizes slash star comments (C type comments) or not. When the boolean variable is set to true it indicates that this StreamTokenizer recognizes slash star comments otherwise slash star comments are not used especially.
• slashStarComments() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• slashStarComments() method does not throw an exception at the time of identifying slash star comments.

Syntax:

    public void slashStarComments(boolean status);

Parameter(s):

• boolean status – This parameter is set to true when it recognizes and avoid slash start comments (i.e. C based comments).

Return value:

The return type of the method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void slashStarComments(boolean status)
// method of StreamTokenizer

import java.io.*;

public class SlashStarComments {
    public static void main(String[] args) {
        String str = "Hi, This is \n a mathematical expression :\n " +
            " 2 * 4 = 8 /*" + "8 + 5 = 13";

        try {
            // Instantiates FileOutputStream  and ObjectOutputStream 
            FileOutputStream fos_stm = new FileOutputStream("D:\\includehelp.txt");
            ObjectOutputStream obj_out_stm = new ObjectOutputStream(fos_stm);

            // By using writeUTF() method is to
            // write the given string in the file
            obj_out_stm.writeUTF(str);
            obj_out_stm.flush();

            // Instantiates FileOutputStream  and ObjectOutputStream 
            ObjectInputStream obj_in_stm = new ObjectInputStream(new FileInputStream("D:\\includehelp.txt"));

            // Instantiates StreamTokenizer and Reader
            Reader reader = new BufferedReader(new InputStreamReader(obj_in_stm));
            StreamTokenizer st = new StreamTokenizer(reader);

            // By using slashStarComments() method is to
            // set comments when boolean set to true and
            // when it encounters '/*' in str
            st.slashStarComments(true);

            // Here, we are considering initially 
            // file is not empty
            boolean end_of_file = false;

            while (!end_of_file) {
                // By using nextToken() method is to
                // parse the next token from the stream
                int token = st.nextToken();

                switch (token) {
                    case StreamTokenizer.TT_EOF:
                        System.out.println("End of File Found");
                        end_of_file = true;
                        break;

                    case StreamTokenizer.TT_EOL:
                        System.out.println("End of Line Found");
                        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 + " Found.");
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Output

word: BHi
, Found.
word: This
word: is
word: a
word: mathematical
word: expression
: Found.
number: 2.0
* Found.
number: 4.0
= Found.
number: 8.0
End of File Found