Ngon.java

/* *****************************************************************************
 *  Name:              Ada Lovelace
 *  Coursera User ID:  123456
 *  Last modified:     October 16, 1842
 **************************************************************************** */

public class Ngon {
    public static void main(String[] args) {
        int n = Integer.parseInt(args[0]);
        double angle = 360.0 / n;
        int canvasSize = Integer.parseInt(args[1]);
        StdDraw.setCanvasSize(canvasSize, canvasSize);
        StdDraw.setScale(0, canvasSize);

        // actual calculation to find length of one side of an N-gon
        double k = (n - 2) * 90.0 / n;
        double step = 0.5 * canvasSize * (Math.sin(Math.toRadians(angle))) / Math.sin(
                Math.toRadians(k));
        //

        // double step = canvasSize*Math.sin(Math.toRadians(angle / 2.0));//lecture provided value

        Turtle turtle = new Turtle(0.5 * canvasSize, 0, angle / 2.0);
        for (int i = 0; i < n; i++) {
            turtle.goForward(step);
            turtle.turnLeft(angle);
        }
    }
}