java hashmap overwriting values

Question

I'm trying to use a hashmap to store an int array of 4 integers. when I add to the hashmap it is supposed to add the most recent set of 4 integers and then generate a new set of 4 numbers. But instead it overwrites all values with the newly generated set of 4 integers... This seems weird since I never tell it to do so. Any ideas? Here is the code where it gets added

System.out.println("Games Played: " + gamesPlayed);
System.out.println("Size Before: " + scoreAnswer.size());
scoreAnswer.put(gamesPlayed, answer); //gamesPlayed will increase by 1 every time right after
System.out.println("Size After: " + scoreAnswer.size());
for (int i = 0; i < maxPin; i++) {
    System.out.println(answer[i]);
}
System.out.println("hash");
for (int i = 0; i < scoreAnswer.size(); i++) {
    int[] a = scoreAnswer.get(i);
    for (int j = 0; j < a.length; j++) {
        System.out.println("[" + i + "]"  + a[j]);
    }
}
gamesPlayed++;
System.out.println("Games Played: " + gamesPlayed);

when I run the program and have it add to the hashmap this is what will print out:

Games Played: 0, Size Before: 0, Size After: 1, 4 0 0 4, hash [0]4 [0]0 [0]0 [0]4 Games Played: 1

Everything is working here, untill i have it add another to the hash, it will then return this:

Games Played: 1, Size Before: 1, Size After: 2, 4 2 0 4, hash [0]4 [0]2 [0]0 [0]4 [1]4 [1]2 [1]0 [1]4, Games Played: 2

As you can see, the first set of integers have been overwritten to the 2nd set of integers. I have no idea why this is happening. Any help is appreciated!

EDIT: So sorry, my computer posted the question before I was finished typing all of my code.

What do you mean by "all the values"? It doesn't help that we don't know any of the types involved. A short but complete program demonstrating the problem would make it easier to help you. — Jon Skeet
– Jon Skeet, Commented Jan 6, 2015 at 20:15
We need an MCVE and a better problem statement to answer this. Your current description sounds vaguely to me like this has nothing to do with the Map but rather a misunderstanding of how array references work. — Radiodef
– Radiodef, Commented Jan 6, 2015 at 20:18
It looks like you should be using a List rather than a Map as the keys appear to be 0, 1, 2, ... . You still haven't given us a MCVE. We need a complete example including the declaration of scoreAnswer. — Paul Boddington
– Paul Boddington, Commented Jan 6, 2015 at 20:27

chancea · Accepted Answer · 2015-01-06 20:38:03Z

3

Based on your code, the variable "answer" must be the array you want to put into the hashmap, I guess you need to initialize it every time using the new keyword, like this

int[] answer = new int[4];

edited Jan 6, 2015 at 20:38

chancea

5,9683 gold badges31 silver badges40 bronze badges

answered Jan 6, 2015 at 20:28

John Ding

1,35011 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Bryce Hahn Over a year ago

Thank you very much, that was what I was missing, everything is working now

Collectives™ on Stack Overflow

java hashmap overwriting values

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related