Do you know why the array takes the value of another array?

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Hi, I am programming a little game and have a problem now:
The integer array yourField[0][0] has the value 0
The integer array opponentsField[0][0] has also the value 0
row and column are 0

opponentsField[row][column - 13] = 2;

after this code the value opponentsField[0][0] has of course changed to 2. But also the value of yourField[0][0] has changed to 2. What could be a reason for that? It is really weird and I have no idea why it happens.
Thank you for answers!

What I have tried:

I have tried to see what happens with the debugger.

Posted 28-Jan-17 5:14am

OnLearn

Updated 28-Jan-17 5:56am

v2

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Thomas Daniels 28-Jan-17 11:15am

How are opponentsField and yourField defined? Can you show these lines of code?

Peter Leow 28-Jan-17 11:32am

Read your question from the point of a stranger. Are you able to understand your question?

Richard MacCutchan 28-Jan-17 11:50am

They are most likely the same array. You need to declare them separately.

OnLearn 28-Jan-17 12:23pm

I haven't done it like yourField = opponentsField;
I have a third array called field[][].
Then I built yourField like this: yourField[][]=Arrays.copyOf(field[][],10);
I gave field other values and built opponentsField equally.

If I initialize the array with copyOf() it isn't a pointer to an array, is it?

Richard MacCutchan 28-Jan-17 12:37pm

I'm still not sure what you are doing. Please edit your question and show the actual code so we can see the sequence of events clearly.

OnLearn 28-Jan-17 13:52pm

the code is more than 500 rows long so I don't think that you want to study it

Richard MacCutchan 29-Jan-17 3:31am

No. I don't, but if you cannot figure out which lines are relevant to the problem, and just post them, then there is not much more we can do.

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OriginalGriff · Answer 1 · 2017-01-28T05:50:00

At a guess, when you created the array variables, either you assigned them both to the same area of memory, or you didn't assign them at all.
If you create your arrays like this:

int[] anArray;
anArray = new int[10];
int[] anotherArray = anArray;

then both array variables anArray and anotherArray share the same memory - so anything you do via one affect the memory the other uses.
You need to assign them separately:

int[] anArray;
anArray = new int[10];
int[] anotherArray;
anotherArray = new int[10];

to get separate memory for each.

Patrice T · Answer 2 · 2017-01-28T05:56:00

Solution 2

yourField and opponentsField are not arrays, they are pointers to an array.
And my guess is that you built 1 from the other

Java

yourField= opponentsField

making both pointers to the same array.

You need to improve your knowledge of Java.

Posted 28-Jan-17 5:56am

Patrice T

Updated 28-Jan-17 5:57am

v2