Array overwritten

[Rob Brew]

Hi all.


I'm building a version of battleships, two arrays are created, x and y, when added to the array list Ships. When i run the program i get the same variables appearing in each instance of the array. Any ideas?

import java.util.*;

public class Ship {
ArrayList<Ship> Ships = new ArrayList<Ship>();
    int[] x = {0, 0, 0, 0};
    int[] y = {0, 0, 0, 0};

    public Ship() {
        
    }

    public Ship(int x[], int y[]) {
        this.x = x;
        this.y = y;
    }

    public void printShip() {
        for (int i = 0; i < x.length; i++) {
            System.out.print(x[i]);
        }
        for (int i = 0; i < y.length; i++) {
            System.out.print(y[i]);
        }
        System.out.println();
    }

    public boolean hit(int tryX, int tryY) {
        boolean hitx = false;
        boolean hity = false;
        for (int i = 0; i < x.length; i++) {
            if (tryX == x[i]) {
                hitx = true;
            }
        }
        for (int i = 0; i < y.length; i++) {
            if (tryY == y[i]) {
                hity = true;
            }
        }
        return (hitx && hity);

    }
    static public void init() {
        int x[] =  new int [4];
        int y[] = new int [4];
        ArrayList<Ship> Ships = new ArrayList<Ship>();
        
      
        for (int k = 0; k < 3; k++) {
        int startx = (int) (Math.random() * 8);
        int starty = (int) (Math.random() * 8);
        int length = (int) (Math.random() * 3);
        int direction = (int) (Math.random() * 2);

            System.out.println(startx + " and " + starty +" dir " + direction);
            switch (direction) {
                case 0:
                    for (int j = 0; j <= 3; j++) {
                        y[j] = starty;
                        x[j] = startx + j;
                    }
                    break;
                case 1:
                    for (int j = 0; j <= 3; j++) {
                        x[j] = startx;
                        y[j] = starty + j;
                    }
                    break;
                default:
                    System.out.println("error");
            }
            Ships.add(new Ship(x, y));
            System.out.println("added");
            
        }
        for (Ship ship : Ships) {
            ship.printShip();
        }
        

    }
}

[Ryan Beckett]

The member x of each instance of Ship refers to same array instance created in init(). It's the same for y. You need to create a new ones.

Ships.add(new Ship(x, y));  
System.out.println("added");
x = new int[4], y = new int[4];