CODEWITHSUNDEEP
java
user1188752
user1188752

Reputation: 27

Issue with using arrays in java?

So, I have a class Square and I am trying to use an array for it board. Here is my code:

public class Square{
   public int pcolor;
   public int contains;
   public int xPos;
   public int yPos;
   Square(int xp,int yp,int pc,int cont){
       xPos=xp;
       yPos=yp;
       contains=cont;
       pcolor=pc;
   }
};
Square[] board = new Square[64];
board[0].xPos=0;

This gives me unexpected token: [ on board[0].xpos=0;. Can anyone help me resolve this?

EDIT:

OK, I moved board[0].xpos=0; inside a method; now it gives me NullPointerException. What do I do?

Upvotes: 0

Views: 111

Answers (3)

Marsellus Wallace
Marsellus Wallace

Reputation: 18611

All the Squares in board are null and you're trying to access a field of a null Object...

You can initialize the array with:

for(int i = 0; i < board.length; i++)
    board[i] = new Square(...something_here...);

Also, I'm not sure what you're trying to do, but you should consider using a Square[][]!

Upvotes: 0

amit
amit

Reputation: 178521

You are trying to make a statement not inside a method or a static scope.

The statement board[0].xPos = 0; should [probably] be inside a method.

You also seem to have a redundant };

This code compiles just fine:

public class Square{
    public int pcolor;
    public int contains;
    public int xPos;
    public int yPos;
    Square(int xp,int yp,int pc,int cont){
        xPos=xp;
        yPos=yp;
        contains=cont;
        pcolor=pc;
    }
    Square[] board = new Square[64];
}

To initialize [and access] elements in board - you will have to do it in a method or in the constructor.

Upvotes: 3

invariant
invariant

Reputation: 8900

Well, if you do this correctly you will get NullPointerException because you didn't create any object yet. My guess is you did some syntax error.

Upvotes: 1

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