Sierpinski.java

Below is the syntax highlighted version of Sierpinski.java from §2.2 Libraries.

/******************************************************************************
 *  Compilation:  javac Sierpinski.java
 *  Execution:    java Sierpinski n size
 *  Dependencies: StdDraw.java
 *
 *  Play chaos game on triangle to produce Sierpinski triangle.
 *  Plots n points.
 *
 *  % java Sierpinski 10000
 *
 ******************************************************************************/

public class Sierpinski {

    public static void main(String[] args) {
        int n = Integer.parseInt(args[0]);
        double[] cx   = { 0.000, 1.000, 0.500 };
        double[] cy   = { 0.000, 0.000, 0.866 };

        double x = 0.0, y = 0.0;
        for (int i = 0; i < n; i++) {
            int r = StdRandom.uniformInt(3);
            x = (x + cx[r]) / 2.0;
            y = (y + cy[r]) / 2.0;
            StdDraw.point(x, y);
        }
    }
}