Taking values from an input file and adding to an integer array line by line (java)

Question

Essentially I have a file of lines of integers. Each line has 9 digits. And I want to read the file. And then input each line into its an array. I want the array to be the same one each time. As I am going to do some processing to the array created from the first line. And then process the same array using a different line.

My input file is as follows:

8 5 3 8 0 0 4 4 0
8 5 3 8 0 0 4 2 2

And the current code that I am using is:

 BufferedReader br = new BufferedReader(new FileReader("c:/lol.txt"));
            Scanner sc = new Scanner(new File("c:/lol.txt"));
            String line;
            while (sc.hasNextLine()){
                line = sc.nextLine();
                int k = Integer.parseInt(line);

Now clearly I should be doing something more, I am just not really sure how to go about it.

Any help is greatly appreciated.

Have you run your code? It should throw an exception here: int k = Integer.parseInt(line); because a whole line can't be converted to one number. (There are many digits and spaces). Also you create a BufferedReader and never use it. Is your question how to finish your program? — jlordo
– jlordo, Commented Nov 12, 2012 at 20:52
Adding to jlordo's comment, you'll want to grab the integer values based on a space delimiter . line.split(" "); — WilliamShatner
– WilliamShatner, Commented Nov 12, 2012 at 20:57
What do you mean with "As I am going to do some processing to the array created from the first line. And then process the same array using a different line." exactly? — Anton Bessonov
– Anton Bessonov, Commented Nov 12, 2012 at 21:18

Anton Bessonov · Accepted Answer · 2012-11-12 21:27:50Z

1

Try:

import java.util.Scanner;
import java.io.File;

public class Test {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(new File("c:/lol.txt"));

        while (sc.hasNext()) {
            String line = sc.nextLine();
            // get String array from line
            String[] strarr = line.split(" "); // attention: split expect regular expression, not just delimiter!
            // initialize array
            int[] intarr = new int[strarr.length];
            // convert each element to integer
            for (int i = 0; i < strarr.length; i++) {
                intarr[i] = Integer.valueOf(strarr[i]); // <= update array from new line
            }
        }
    }
}

Of course, you should handle exception instead to pass it.

edited Nov 12, 2012 at 21:27

answered Nov 12, 2012 at 20:58

Anton Bessonov

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4 Comments

WilliamShatner Over a year ago

Basically did the whole assignment for him aside from adding them to an integer array. Add some comments in there for he understands what is happening :)

Anton Bessonov Over a year ago

I think I completely misunderstood the question... I updated my answer.

Geobits Over a year ago

I'd move the int array assignment and change it to int[] intarr = new int[strarr.length]; also, to work with different lengths.

Anton Bessonov Over a year ago

It's was my second version, but "As I am going to do some processing to the array created from the first line.". Comment this now on question.

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