How to find out user votes and winner of election code? [closed]

I can’t seem the get the right amount of votes for the user inputted name and I can’t figure out how to get the most popular name declared as the winner. I do get how many times I’ve voted for someone but it’s not always right. Sometimes I get an ArrayIndexOutOfBounds Exception error and I think it has to do something with the Candidate get and Vote get print in the end.

This is how it supposed to be.

That’s how I managed to do it so far.

public class JavaApplication16 {

    public static void main(String[] args) {


        ArrayList<String> Names = new ArrayList<String>();

        ArrayList<Integer> Votes = new ArrayList<Integer>();
        Scanner input = new Scanner(System.in);

        System.out.println("Enter the name you wish to vote for: ");
        String addName = input.nextLine();

        while (addName.length() != 0) {
            if (Names.contains(addName)) { // Name already in the array
                int i = Names.indexOf(addName); // Add some code to find the index of the name in the Names array
                Integer j = Votes.get(i);   // Find out how many votes they currently have
                j++;    // Increment it by 1
                Votes.set(i, j); // Put the new number of votes back into the Votes array at the correct index
                //Votes.indexOf(addName);// Increment the contents of the Votes array at the same index

                //break;
            }
            if (addName.equals("-0")) {
                System.out.println("List of the Candidates");
                break;

            } else { // Name not in the array
                Names.add(addName); // Add the name to the end of the list
                Votes.add(1); // They have one vote so far, so set their vote count to 1
            }

            addName = input.nextLine();

        }
        //End of the while loop to vote

        //A List to remove the duplicates from the Name list
        ArrayList<String> Candidate = new ArrayList<String>();
        for (String nam : Names) {
            if (!Candidate.contains(nam)) {
                Candidate.add(nam);
            }
        }

        for (int t = 0; t < Candidate.size(); t++) {

        }
        for (int i = 0; i < Names.size(); i++) {

        }
        for (int j = 0; j < Votes.size(); j++) {

        }  // The following is a basic example - you could use a for loop and make the output look better

        System.out.println(Candidate.get(0) + " recieved " + (Votes.get(0) + " vote. "));
        System.out.println(Candidate.get(1) + " recieved " + (Votes.get(1) + " vote. "));
        System.out.println(Candidate.get(2) + " recieved " + (Votes.get(2) + " vote. "));
        System.out.println(Candidate.get(3) + " recieved " + (Votes.get(3) + " vote. "));


        // Code to find out the highest amount of votes
        System.out.println("AND THE WINNER IS");
        System.out.println(Collections.max(Names));
        System.out.println(Collections.max(Votes));

    }
}

Answer

You use illegal data stryctyre for your goal. You use List, but you have to count the votes for each name. So you have to use Map<String, Integer> where key is the name and value is the amount of votes.

Additionally, you have to sort these names by votes. So you could create a new list with all entries form this map and then sort these names by votes desc. But I prefer to use another data structure PriorityQueue tha internally sorts the entries.

public static void main(String... args) {
    System.out.println("#######################################");
    System.out.println("# Enter the votes, one vote per line. #");
    System.out.println("# End with either -1 or an empty line.#");
    System.out.println("#######################################");
    System.out.println();

    Scanner scan = new Scanner(System.in);
    Map<String, Integer> votes = new HashMap<>();

    while (true) {
        String name = scan.nextLine().trim();

        if (name.isEmpty() || "-1".equals(name))
            break;

        votes.put(name, votes.getOrDefault(name, 0) + 1);
    }

    if (votes.isEmpty())
        System.out.println("No Votes.");
    else {
        final Comparator<Map.Entry<String, Integer>> sortByVotesDesc = (one, two) -> Integer.compare(two.getValue(), one.getValue());
        Queue<Map.Entry<String, Integer>> queue = new PriorityQueue<>(sortByVotesDesc);
        queue.addAll(votes.entrySet());

        Map.Entry<String, Integer> winner = queue.element();

        while (!queue.isEmpty()) {
            Map.Entry<String, Integer> vote = queue.remove();
            System.out.format("%s received %d votesn", vote.getKey(), vote.getValue());
        }

        System.out.println("------------------------");
        System.out.format("The Winner is %s with %d votesn", winner.getKey(), winner.getValue());
    }
}

Demo

#######################################
# Enter the votes, one vote per line. #
# End with either -1 or an empty line.#
#######################################

Sam
Peter
James
Sam
Sam
Peter
Sam

Sam received 4 votes
Peter received 2 votes
James received 1 votes
------------------------
The Winner is Sam with 4 votes