Java 2d array of objects

Question

I have a cell object with function

public class Cell {
    static int X;
    static int Y;
    static int Val = 0;
    static int Player = 0;

    public Cell(int a, int b, int p) {
        // TODO Auto-generated constructor stub
        X = a;
        Y = b;
        Val = 0;
        Player = p;
    }

With additional function updateX, updateY, updateVal, updatePlayer and respective get functions. It is called by

    Cell[][] grid = new Cell[7][6];
    for(int i = 0; i < 7; i++)
            for(int j = 0; j < 6; j++)
            {
            grid[i][j] = new Cell(i, j, 0);         
            }       
        System.out.println("wasd");
        grid[0][1].updatePlayer(1); 
        grid[0][1].updateVal(1);

        System.out.println("grid[0][1].getval = " + grid[0][1].getVal() + " grid[1][1].getval = " + grid[1][1].getVal());

But the output is

grid[0][1].getval = 1 grid[1][1].getval = 1

and should be

grid[0][1].getval = 1 grid[1][1].getval = 0

What is causing this error?

Don't use static variables and methods unless you've got good reason for doing so -- you don't and as a matter of fact have strong reason for not doing this. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Feb 9, 2012 at 2:34

plucury · Accepted Answer · 2012-02-09 02:37:43Z

2

static int X;
static int Y;
static int Val = 0;
static int Player = 0;

These properties should not be static,following code should be ok:

int X;
int Y;
int Val;//the default int value is zero 
int Player;

answered Feb 9, 2012 at 2:37

plucury

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Comments

Perception · Accepted Answer · 2012-02-09 02:32:32Z

2

You made the X, Y, Val and Player variables in the class static. Which means they are shared by all instances of that class, which means their values in all those instances will be exactly the same. I'm pretty sure you wanted to declare those as instance variables instead:

public class Cell {
    private int x, y, val, player;
    // ...
}

answered Feb 9, 2012 at 2:32

Perception

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1 Comment

Hovercraft Full Of Eels Over a year ago

It's not just the x and y fields -- he's made all the fields static when none should be.

Hunter McMillen · Accepted Answer · 2012-02-09 02:35:31Z

2

You made Val a static variable, so only one Val variable exists and it is shared by all Cell objects.

change:

static int Val = 0;

to:

int Val = 0;

Similarly if you want individual Cell objects to retain separate instances of your variables (i.e. x,y,Val) you need to take away the static keyword from all of them

answered Feb 9, 2012 at 2:35

Hunter McMillen

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