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Thread: Jumps over while-loop

  1. #1
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    Default Jumps over while-loop

    Hello!

    I'm creating a program with the source code below. It doesn't work, because it seems to jump over the while-loop. The code:

    public class Ordjaktsfusk
    {
     
        public static void main(String[] args)throws FileNotFoundException, IOException
        {
            int plats2, plats3;
            String finalOrd = "";
     
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("Vilka bokstäver? ");
     
            String bok = in.readLine();
     
            Scanner fil = new Scanner(new File("ord.txt"));
     
            while (fil.hasNext())
            {
                String testOrd = fil.nextLine();
     
                hittaOrd:
                if (bok.charAt(0) == testOrd.charAt(0))
                {
     
                    if(testOrd.indexOf(bok.charAt(1))>-1)
                    {
                        plats2 = testOrd.indexOf(bok.charAt(1));
                        plats3 = testOrd.indexOf(bok.charAt(2));
                    }
                    else
                    {
                        break hittaOrd;
                    }
     
                    if(plats3>plats2)
                    {
                        if (testOrd.length()>finalOrd.length())
                        {
                           finalOrd = testOrd;
                        }
                    }
                    else
                    {
                        break hittaOrd;
                    }
     
                }
     
            }
     
            System.out.println(finalOrd);
        }
    }


  2. #2
    Super Moderator jps's Avatar
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    Default Re: Jumps over while-loop

    What would cause the while loop to be skipped?

    Since the while loop appears in main, we can assume for now that main is being called...
    What is the value of fil.hasNext() the first time the while loop is encountered?
    Try a print line before the while loop to see the value of fil and fil.hasNext() and see what is going on

  3. The Following User Says Thank You to jps For This Useful Post:

    iHank (April 9th, 2013)

  4. #3
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    Default Re: Jumps over while-loop

    Ok, I tested "fil.hasNext" before the While-loop, and the value was "false". The value of "fil" was:

    java.util.Scanner[delimiters=\p{javaWhitespace}+][position=0][match valid=false][need input=false][source closed=false][skipped=false][group separator=\*][decimal separator=\,][positive prefix=][negative prefix=\Q-\E][positive suffix=][negative suffix=][NaN string=\Q�\E][infinity string=\Q∞\E]

    I really can't figure out what is wrong. The file does exist and it is not empty.

    --- Update ---

    Ok, I tested "fil.hasNext" before the While-loop, and the value was "false". The value of "fil" was:

    java.util.Scanner[delimiters=\p{javaWhitespace}+][position=0][match valid=false][need input=false][source closed=false][skipped=false][group separator=\*][decimal separator=\,][positive prefix=][negative prefix=\Q-\E][positive suffix=][negative suffix=][NaN string=\Q�\E][infinity string=\Q∞\E]

    I really can't figure out what is wrong. The file does exist and it is not empty.

  5. #4
    Super Moderator Norm's Avatar
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    Default Re: Jumps over while-loop

    A common cause of this problem is there is more than one version of the file present in different folders and the program is trying to read the wrong one.

    How are you executing the program?
    If you don't understand my answer, don't ignore it, ask a question.

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

    iHank (April 9th, 2013)

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    Default Re: Jumps over while-loop

    Okey, thanks! I'm executing the program through Netbeans - run file. I found a solution:

    I just replace Scanner fil = new Scanner(new File("ord.txt")) with Scanner fil = new Scanner(new FileReader("ord.txt")).

    Why does that work and not just with "File"? I don't have a clue.

    Another question: Do you recommend having "String testOrd = fil.nextLine()" inside the while-loop or is it another solution? A new object is created for each lap and the old ones will act as garbage in the memory. I've read that Java can sort this out by itself, but it may slow the execution down a bit.

  8. #6
    Super Moderator Norm's Avatar
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    Default Re: Jumps over while-loop

    Look at the contents of the ord.txt file in a hex editor and see what the first few characters of the file is.

    What OS are you on?
    If you don't understand my answer, don't ignore it, ask a question.

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