LACS07_Koch.java

/**
Koch.java   MrG 2012.0607
purpose:    graph a Koch curve
required files: Koch.java           main class
        Turtle.java         derived class
        StdDraw.java            graphics class
translator: java Koch.java
interpreter:    java Koch N
*/
public class Koch
{
    public static void koch(int n, double step, Turtle turtle)
    {
        if(n==0)
        {
            turtle.goForward(step);
            return;
        }
        koch(n-1,step,turtle);
        turtle.turnLeft(60);
        koch(n-1,step,turtle);
        turtle.turnLeft(-120);
        koch(n-1,step,turtle);
        turtle.turnLeft(60);
        koch(n-1,step,turtle);
    }

    public static void main(String[] args)
    {
        StdDraw.setXscale(0,1.5);
        StdDraw.setYscale(0,1.5);
        int N = Integer.parseInt(args[0]);
        Turtle blaise = new Turtle(0,1,0);
        koch(N,1/Math.pow(3,N),blaise);
        blaise.turnLeft(-120);
        koch(N,1/Math.pow(3,N),blaise);
        blaise.turnLeft(-120);
        koch(N,1/Math.pow(3,N),blaise);
    }
}