Java GUI draw tree using random number

Question

How can I make this tree's angle and depth to be random by using 'random number'?

In the below code JFrame is been used. The intent behind the question is to get the idea of randomizing the angles and the depth, which is passed in the paint method.

public class DrawTreeFrame extends JFrame {
    
    public DrawTreeFrame() {
        setSize(800, 700);
        
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
    
    private void drawTree(Graphics g, int x1, int y1, double angle, int depth) {
        if(depth==0)
            return;
        int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 10.0);
        int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 10.0);
        g.drawLine(x1, y1, x2, y2);
        drawTree(g, x2, y2, angle-20, depth-1);
        drawTree(g, x2, y2, angle+20, depth-1);
    }
    
    @Override
    public void paint(Graphics g) {
        g.setColor(Color.BLACK);
        drawTree(g, 400, 600, -90, 10);
    }

    public static void main(String[] args) {
        new DrawTreeFrame();

    }

}

Answer 1

You can use Math.random(). The following code method will give you random numbers in a range;

public int getRandomNumber(int min, int max) {
    return (int) ((Math.random() * (max - min)) + min);
}

Ultimately your code should look like this:-

class DrawTreeFrame extends JFrame {
    
    public DrawTreeFrame() {
        setSize(800, 700);
        
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
    
    private void drawTree(Graphics g, int x1, int y1, double angle, int depth) {
        if(depth==0)
            return;
        int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 10.0);
        int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 10.0);
        g.drawLine(x1, y1, x2, y2);
        drawTree(g, x2, y2, angle-20, depth-1);
        drawTree(g, x2, y2, angle+20, depth-1);
    }
    
    @Override
    public void paint(Graphics g) {
        g.setColor(Color.BLACK);
        int x1 = getRandomNumber(100, 400);
        int y1 = getRandomNumber(400, 800);
        double angle = getRandomNumber(-10, -100);
        int depth = getRandomNumber(5, 20);
        drawTree(g, x1, y1, angle, depth);
    }

    public int getRandomNumber(int min, int max) {
        return (int) ((Math.random() * (max - min)) + min);
    }
    
    public static void main(String[] args) {
        new DrawTreeFrame();

    }

}