CODEWITHSUNDEEP
javaarrays
Berkant Levent
Berkant Levent

Reputation: 5

2D Arrays Battleship place random ships

Hi, I just started to create a battleship game and I would like to know how to place random ships in my 2D Array. Here is the code for 2D Array.

public class javaapplication24 {

    public static void main(String[] args) {
        int[][] table = new int[10][10];
        int i,j,k;
        for(i=0;i<table.length;i++){
            for(j=0;j<table.length;j++){
                System.out.print(table[i][j]+" ");
            }
            System.out.println();
        }
    }
}

Upvotes: 0

Views: 3302

Answers (1)

John Coleman
John Coleman

Reputation: 52008

The problem that you have undoubtedly noticed is that as each ship is placed, it rules out possibilities of where subsequent ships can be placed. The easiest way around the difficulty is just trial and error. First write a function for randomly placing a ship of a given size somewhere on the board. Place the ships using a nested loop. The outer loop could be a for-loop which iterates through the ships to be placed. The inner loop can be a while loop (or maybe a do-loop) that repeatedly calls the ship-placing function to get a candidate placement, then checks if it clashes with previous choices, looping until a clash-free placement is found.

As far as placing a single ship goes:

1) First generate a random number which is either 0 or 1 to determine if the ship will be placed horizontally or vertically

2) Then pick a random number to determine what the row or column it will be in

3) Finally, pick a random number for the first square in the row or column that contains the ship. The size of the ship will enter in here. If it has length 3, for example, then there are only 10-3 = 7 possible choices for the first square (assuming a standard 10x10 board).

On Edit: @Manus raised a good point about difficulties that would be encountered if the number of ships are above a certain threshold. If you have a massive fleet of ships on a small board it is possible that certain partial placements (of some of the ships) would rule out any valid placement of the remaining ships. The only way I see around this difficulty is to use a back-tracking approach that checks if there is enough room for a ship before trying to place it and, if not, revisit the placement of previous ships until you get something that works. But -- the work involved in checking if there is any valid position can be done in such a way that you simultaneously determine the set of valid positions, in which case you might as well directly pick from that set rather than use trial and error. My approach is essentially a quick-and-dirty approach for simulating the child's game. You would need a more sophisticated approach if you want a more flexible game.

Upvotes: 2

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