Question

I am creating a game of Battleships using Java and I am having trouble generating 2 random numbers which randomly choose a place on the battleship board. For example, the computer has to randomly choose a space on the board to place the ships (and later to shoot on).

I have created a 2D array:

int rows = 10;
int cols = 10;
char [][] grid;
grid = new char[rows][cols];

And then tried several different ways to get the two random numbers in the array but I cannot get it to work. Here is an example of what I have tried:

int randomPos = (char) (Math.random() * (grid[rows][cols] + 1));

Please ask me some questions if this doesn’t make sense.

Sean

Answer 1

Math.random() generates a decimal number. It doesn’t make any sense to have square 3.5779789689689... (or whatever you’re referring to), so use the Math.floor() method, which rounds the number inside to the nearest integer. And as @Sanjay explained, generate the numbers separately…

int row = (int) Math.floor(Math.random() * rows);
int col = (int) Math.floor(Math.random() * cols);

Now you have actual integers that you can work with.