Why is my program printing out only the last object value of the array?

Question

Candidate class:

public class Candidate 
{
    private static String name;
    private static int numVotes;

    Candidate(String name, int numVotes)
    {
        Candidate.name = name;
        Candidate.numVotes = numVotes;
    }

    public String toString()
    {
        return name + " recieved " + numVotes + " votes.";
    }

    public static int getVotes()
    {
         return numVotes;
    }

    public static void setVotes(int inputVotes)
    {
         numVotes = inputVotes;
    }

    public static String getName()
    {
        return name;
    }

    public static void setName(String inputName)
    {
        name = inputName;
    }
}

TestCandidate class:

public class TestCandidate 
{
    public static Candidate[] election = new Candidate[5];

    public static void addCandidates(Candidate[] election)
    {
        election[0] = new Candidate("John Smith", 5000);
        election[1] = new Candidate("Mary Miller", 4000);
        election[2] = new Candidate("Michael Duffy", 6000);
        election[3] = new Candidate("Tim Robinson", 2500);
        election[4] = new Candidate("Joe Ashton", 1800);
    }


    public static int getTotal(Candidate[] election)
    {
        int total = 0;

        for (Candidate i : election)
        {
            total += Candidate.getVotes();
        }

        return total;
    }

    public static void printResults(Candidate[] election)
    {
        System.out.printf("%s%12s%25s", "Candidate", "Votes", "Percentage of Votes\n");

        for (Candidate i: election)
        {
            System.out.printf("\n%s%10s%10s", Candidate.getName(), Candidate.getVotes(), ((double)Candidate.getVotes()/getTotal(election) * 100));
        }

        System.out.println("\n\nTotal Number of Votes: " + getTotal(election));
    } 

    public static void main (String args[])
    {
        addCandidates(election);
        printResults(election);
    }
}

Whenever I run the TestCandidate class, it outputs this:

Candidate       Votes     Percentage of Votes

Joe Ashton      1800      20.0
Joe Ashton      1800      20.0
Joe Ashton      1800      20.0
Joe Ashton      1800      20.0
Joe Ashton      1800      20.0

Total Number of Votes: 9000

The point of the program is to output all of the candidates and calculate averages based on everyone. I believe it's an issue within my for-each loops. Any help with this would be appreciated.

Likely because your private variables in `Candidate` class are static — Norsk, Apr 16 '16 at 18:15
`static` means you want to have variables which shared across all instances. If you are setting `static`` fields in your constructor it is almost certainly a bug. — Peter Lawrey, Apr 16 '16 at 18:23

score 3 · Accepted Answer · answered Apr 16 '16 at 18:14

3

private static String name;
private static int numVotes;

static members have one value for all the instances of the class. Remove the static keyword in order for different instances to have different values.

answered Apr 16 '16 at 18:14

Eran

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score -2 · Answer 2 · edited Jun 20 '20 at 09:12

If you do this:

private static String name;
private static int numVotes;

every new Candidate object you create will overwrite the fields name and numVotes of ALL other objects because these fields are not objects fields are class fields...

you need to remove the static keyword of those fields in order to work:

Example:

public class Candidate 
{
    private String name;
    private int numVotes;

    Candidate(String name, int numVotes)
    {
        Candidate.name = name;
        Candidate.numVotes = numVotes;
    }
    .... .... ETC ETC

Why is my program printing out only the last object value of the array?

2 Answers2

Example: