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Thread: Problem with Comparator

  1. #1
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    Default Problem with Comparator

    Hello!

    I have a Treemap, and use a comparator, co, in the declaration. The goal is to write the map out in String-size-order.

            static JämförOrd co = new JämförOrd();
     
           static NavigableSet<String> na = new TreeSet<>(co);

    The comparator-class I've made look like this:

    public class JämförOrd implements Comparator<String> {
     
        @Override
        public int compare(String s1, String s2)
        {
            if(s1.length()< s2.length())
            {
                return -1;
            }
            else if (s1.length()>s2.length())
            {
                return 1;        
            }
            else return 0;
     
        }
    }

    When I don't use the comparator, the treemap is written out, but not in string-size-order. When I use the comparator, only a small part of the words are written. Why is that?

    /hank


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Problem with Comparator

    Can you post a small, complete program that compiles, executes and shows the problem?
    only a small part of the words are written
    What Strings are NOT written?
    Have you read the definition for a Set? What will happen when 2 Strings are equal?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Problem with Comparator

    Well, the program is a Scramble-solver, which means that every combination of letters is checked in a dictionary. I guess that a set with that very comparator just have one word at every word length. Is that right?

    // Hank

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    Super Moderator Norm's Avatar
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    Default Re: Problem with Comparator

    just have one word at every word length.
    Yes. There won't be two Strings with equal lengths.
    If you don't understand my answer, don't ignore it, ask a question.

  5. The Following User Says Thank You to Norm For This Useful Post:

    iHank (November 30th, 2013)

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    Default Re: Problem with Comparator

    Thank you, Norm!

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