game of life

Matrix class

package gameoflife;
public class Matrix {
    Boolean[][] matrix;
    int numRows;
    int numCols;

   public Matrix(int rows, int cols) {
        matrix = new Boolean[rows][cols];

        numRows = rows;
        numCols = cols;

    for(int i = 0; i < cols; i++){
        for(int j = 0; j < rows; j++){
        matrix[j][i] = false;
        }
    }
    }
    //constructor with all values false

    public Matrix(int size) {
        matrix = new Boolean[size][size];

        numRows = size;
        numCols = size;

    for(int i = 0; i < size; i++){
        for(int j = 0; j < size; j++){
        matrix[j][i] = false;
        }
    }
    }
    //constructor

    void set(int x, int y, Boolean state){
        matrix[x][y] = state;
    }
    //sets a value within the matrix

    Boolean state(int x, int y){
        return matrix[x][y];
    }
    //gets a value within the matrix

    int rows(){
        return numRows;
    }
    //gets the number of rows in the matrix

    int cols(){
        return numCols;
    }
    //gets the number of columns in the matrix
}

GameGrid class

package gameoflife;
public class GameGrid extends Matrix{

    public GameGrid(int rows, int cols){
        //gameGrid = new Boolean[rows][cols];
        super(rows+2, cols+2);
    }
    //creates a gamegrid with set rows and cols

    public GameGrid(int size){
        //gameGrid = new Boolean[size][size];
        super(size+2) /*me*/;
    }
    //creates a new gamegrid which is size x size

    Boolean isAlive(int x, int y){
        return matrix[x][y];
    }
    //returns the state of a coordinate

    short numNeighbors(int x, int y) {
    short numNeighbors;
        numNeighbors = 0;

        if (matrix[x+1][y] == true) numNeighbors++;
        if (matrix[x][y+1] == true) numNeighbors++;
        if (matrix[x+1][y+1] == true) numNeighbors++;
        if (matrix[x][y-1] == true) numNeighbors++;
        if (matrix[x-1][y] == true) numNeighbors++;
        if (matrix[x+1][y-1] == true) numNeighbors++;
        if (matrix[x-1][y+1] == true) numNeighbors++;
        if (matrix[x-1][y-1] == true) numNeighbors++;

        return numNeighbors;
    }
    //returns the number of neighbours that a coordinate has

    void deactivate(int x, int y){
        matrix[x][y] = false;
    }
    //turns a coord to false

    void activate(int x, int y) {
        matrix[x][y] = true;
    }
    //turns a coord to true

    void nextGen(){
    Boolean[][] newMatrix = new Boolean[rows()][cols()];

        for (int i = 1; i < cols()-1; i++){
            for (int j = 1; j < rows()-1; j++){
        //if a cell has 3 neighbours, become or stay true
                if (numNeighbors(j, i) == 3) newMatrix[j][i] = true;
        //if it doesn't have 3 neighbours, become or stay false
        else newMatrix[j][i] = false;
            }
        }

    matrix = newMatrix;
    }
    //makes matrix represent the next generation

    String showGrid(){
        String arrayOutput = "";
       //writes each row as a line, then goes to the next and does the same.
        for(int k = 1; k < cols()-1; k++) {
            //opens a square bracket on every row of the array
            arrayOutput += "[ ";
            //lists the row in the square brackets with the correct state in each slot
            for(int l = 1; l < rows()-1; l++){
                if (state(l, k))
            {arrayOutput += " * ";}
                else
            {arrayOutput += " . ";}
            }
            //closes the square brackets and then starts a new line for the next row
            arrayOutput += "]\n";
        }
    return arrayOutput;
    }
    //outputs the gamegrid

}

GameOfLife class

package gameoflife;
import javax.swing.JOptionPane;

public class GameOfLife {

    public static void main(String args[]) {
    int width = Integer.parseInt(JOptionPane.showInputDialog("How many spaces wide do you want your grid to be?"));
    int height = Integer.parseInt(JOptionPane.showInputDialog("How many spaces high do you want your grid to be?"));
    GameGrid myGrid = new GameGrid(width, height);

    int numOrganisms = Integer.parseInt(JOptionPane.showInputDialog("How many organisms do you want to plot?"));

    int xcoord;
    int ycoord;

    for (int i = 0; i < numOrganisms; i++){
        xcoord = (1+Integer.parseInt(JOptionPane.showInputDialog("What is the x coordinate of organism #"+(i+1)+"?")));
        ycoord = (1+Integer.parseInt(JOptionPane.showInputDialog("What is the y coordinate of organism #"+(i+1)+"?")));
        myGrid.activate(xcoord, ycoord);
    }

    int numGenerations = Integer.parseInt(JOptionPane.showInputDialog("How many generations do you want to be shown?"));

    for (int j = 0; j < numGenerations; j++){
        JOptionPane.showMessageDialog(null,"generation " + (j+1) + ":\n\n" + myGrid.showGrid());
        myGrid.nextGen();
    }

    }
}