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Thread: Reading and Writing 2d boolean array

  1. #1
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    Default Reading and Writing 2d boolean array

    I have a file that will be in this format:

    12
    1 0 0
    0 1 0
    1 0 1

    where the first line is the count

    and after is the boolean array content

    For reading the array, i count the first line then initialize the N by N boolean array, and then iterate through each line and initialize the boolean array row by row.
    However, my reading function wont work as it keeps saying that the boolean array grid wasn't initialized?

    the error says:
    Error53, 48) java: variable grid might not have been initialized




     
    static void getN(String fileName) throws FileNotFoundException, IOException
        {
            int generation = 0;
            int gridSize = 0;
            BufferedReader buffReader = new BufferedReader(new FileReader("/Users/alkaitoob/IdeaProjects/untitled9/src/test"));
            buffReader.readLine();
            while(buffReader.readLine()!=null)
            {
                gridSize++;
            }
            buffReader.close();
            boolean [][] grid = new boolean[gridSize][gridSize];
     
            Scanner in = new Scanner(new File("/Users/alkaitoob/IdeaProjects/untitled9/src/test"));
            gridSize=in.nextInt();
            //in.nextLine();
            for(int r= 0 ; r<gridSize;r++)
            {
                for(int c= 0;c<gridSize;c++)
                {
                    if(in.nextInt()==1)
                    {
                        grid[r][c] = true;
                    }
                    else {
                        grid[r][c] = false;
                    }
                }
            }
            for(int i=0; i<gridSize; i++)
            {
                for(int j=0; j<gridSize; j++)
                {
                    System.out.print(" " + grid[i][j]);
                }
                System.out.println("\n");
            }
            in.close();
        }
     
    }
    Last edited by Kieve; December 2nd, 2019 at 08:41 AM.

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Reading and Writing 2d boolean array

    There are two sections of code posted. Which one has the error?
    Please copy the full text of the error message and paste it here.

    Please edit your post and wrap your code with code tags:

    [code]
    **YOUR CODE GOES HERE**
    [/code]

    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Reading and Writing 2d boolean array

    Thanks done

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Reading and Writing 2d boolean array

    What source code line is that error message referring to? The posted source does not have all the source code's lines. Where is line 53?

    The compiler thinks It is possible for an exception to throw the execution out of the try{} catch block before grid is assigned a value.
    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:

    Kieve (December 2nd, 2019)

  6. #5
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    Default Re: Reading and Writing 2d boolean array

    thanks fixed my code now it works properly

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