Question

I am trying to read in 10 signed integers from a file into an array and for some reason, it is not happening and I am not getting any errors at compile and runtime. I just wanted a second pair of eyes to look over this and see what I might be missing.

The test file is “input.txt” and contains: -1, 4, 32, 0, -12, 2, 30, 1, -3, -32

Here is my code:

  public void readFromFile(String filename)
  {
     try {
        File f = new File(filename);
        Scanner scan  = new Scanner(f);
        String nextLine;
        int[] testAry = new int[10];
        int i = 0;

        while (scan.hasNextInt())
        {
           testAry[i] = scan.nextInt();
           i++;
        }
     }
        catch (FileNotFoundException fnf)
        {
           System.out.println(fnf.getMessage());
        }
  } 

Answer 1

Your using the default delimiter on the Scanner object.

try using the delimiter ive got in the line useDelimiter(\\s*,\\s*”). Its regex to split up your the input from the file by a comma.

 try {
            File f = new File("input.txt");
            Scanner scan = new Scanner(f);
            scan.useDelimiter("\\s*,\\s*");
            String nextLine; //left it in even tho you are not using it
            int[] testAry = new int[10];
            int i = 0;

            while (scan.hasNextInt()) {
                testAry[i] = scan.nextInt();
                System.out.println(testAry[i]);
                i++;
            }
        } catch (FileNotFoundException fnf) {
            System.out.println(fnf.getMessage());
        }