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Thread: New person Just trying to read a file of ints

  1. #1
    Junior Member
    Join Date
    Mar 2010
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    Default New person Just trying to read a file of ints

    I am trying to read a simple .txt file of ints into a 2D array. However, the scanner object seems to skip the first few ints. The "scanner.hasNext()" seems to advance the scanner. Please let me know what I am doing wrong. I attached the file "input.txt" Thanks

    public int[][] getMatrix(String fileName) 
            int totalrows = 0;
        	int totalcols= 0;
        	int[][] matrix = null;
        	File file = null;
        	Scanner scanner = null;
        	int rowIndex = 0;
        	int colIndex = 0;
        		scanner =new Scanner(new File("input.txt"));
        		catch (FileNotFoundException e1) 
    			// TODO Auto-generated catch block
    			System.out.println ("File not found!");
    		    // Stop program if no file found
    		    System.exit (0);
                 while (scanner.hasNext())
    			 if (scanner.hasNextInt())
    				 totalrows = scanner.nextInt();
    			 if (scanner.hasNextInt())
    				 totalcols = scanner.nextInt();
                    matrix = new int[totalrows][totalcols];
             while (true)
    					if (!scanner.hasNextInt() || !(scanner.next() == "\r") || !(scanner.next() == " "))
    					matrix[rowIndex][colIndex] = scanner.nextInt();
    					if (scanner.next() == "\r")
    						rowIndex = 0;
             return matrix;
    Attached Files Attached Files

  2. #2
    Super Moderator helloworld922's Avatar
    Join Date
    Jun 2009
    Thanked 619 Times in 561 Posts
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    Default Re: New person Just trying to read a file of ints

    The hasNext method doesn't advance the read point. However, in the point where you're reading in data, you use the next() method, which will advance the read point.

    A suggestion would be to simply read in the number of integers that should be in that file.

    for (int i = 0; i < totalrows; i++)
         for (int j = 0; j < totalcols; j++)
              matrix[i][j] = scanner.nextInt();

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