Question

This program below when run does not halt. I don’t think I made a major error but please help me for I’m new in Java.

import java.util.*;
    public class ReverseWords {
    public static void main( String args[] ) {
        String paragraph;
        Scanner input = new Scanner (System.in);

        System.out.print("Enter a paragraph: ");
        paragraph = input.nextLine();
        paragraph = paragraph.trim();
        StringTokenizer tokens = new StringTokenizer(paragraph, ".");
        while (tokens.hasMoreTokens()){

            for (int i = paragraph.length() - 1; i>=0; i--) {
                System.out.print(paragraph.charAt(i));
            }
            System.out.print(". ");
        }
        System.out.println();
    }
    }

When I input: The quick brown fox. Jumps over. The lazy dog.
It outputs: .god yzal ehT .revo spmuJ .xof nworb kciuq ehT. infinite times.

Thank you very much!

Answer 1

Look at this:

 while (tokens.hasMoreTokens())

You’re never fetching the next token. So if that ever returns true, it will keep doing so forever. You probably want (in the while loop):

String token = tokens.nextToken();
for (int i = token.length() - 1; i >= 0; i--) {
    System.out.print(token.charAt(i));
}
System.out.print(". ");

That’s assuming you want to reverse each partial-sentence within each line. It’s not really clear what your aim is.