Question

I’m attempting to grab data sets from a file named poll.txt and then use relevant data.

The content of the poll.txt:

CT 56 31 7 Oct U. of Connecticut

NE 37 56 5 Sep Rasmussen

AZ 41 49 10 Oct Northern Arizona U.

The source code, ElectoralVotes.java:

import java.io.*;
import java.util.*;

public class ElectionResults {

    public static void main(String[] args) throws FileNotFoundException {
        int dVotes = 0;
        int sVotes = 0;

        Scanner scanner = new Scanner(new File("poll.txt"));
        String[] nonDigits = new String[29];
        int[] Digits = new int[10];
        int i = 0;
        int j = 1;
        while (scanner.hasNextLine()) {
            while (scanner.hasNext()) {
                nonDigits[i++] = scanner.next();
            }
            i = 0;
            while (j <= 3) {
                Digits[i] = Integer.parseInt(nonDigits[j]);
                i++;
                j++;
            }

            if (Digits[0] > Digits[1]) {
                sVotes += Digits[2];
            } else {
                dVotes += Digits[2];
            }
            scanner.nextLine();
        }
    }
}

However when I run the program, only one of the lines is being used before giving an exception:

Exception in thread "main" java.util.NoSuchElementException: No line found error.

I’ve tried moving around the “scanner.nextLine();” statement to no avail.
The program works fine if I don’t ask for a nextLine but I obviously need it, and I can’t seem to figure out what’s wrong.

Answer 1

You’re calling scanner.nextLine() at the end of your loop, which will try read the next line. You’re then just throwing away the data!

I suspect that’s throwing the exception, because you’ve run out of data. I suspect that your loop of:

while(scanner.hasNext()){
   nonDigits[i++] = scanner.next();
}

is completely consuming the data. (The behaviour of Scanner has never been terribly clear to me from the docs, admittedly.) I suspect you should actually be reading a line at a time, with:

while (scanner.hasNextLine()) {
    String line = scanner.nextline();
    // Now use line
}

… and parsing the line separately.