little help

package argeaer;
import robocode.*;
//import java.awt.Color;

/**
 * Arg - a robot by (your name here)
 */
public class Arg extends Robot
{
	/**
	 * run: Arg's default behavior
	 */
	public void run() {
		// After trying out your robot, try uncommenting the import at the top,
		// and the next line:
		//setColors(Color.red,Color.blue,Color.green);
		while(true) {
			// Replace the next 4 lines with any behavior you would like
			ahead(100);
			turnGunRight(360);
			back(100);
			turnGunRight(360);
		}
	}

	/**
	 * onScannedRobot: What to do when you see another robot
	 */
/**This function predicts the time of the intersection between the 
bullet and the target based on a simple iteration.  It then moves 
the gun to the correct angle to fire on the target.**/
void doGun() {
    long time;
    long nextTime;
    Point2D.Double p;
    p = new Point2D.Double(target.x, target.y);
    for (int i = 0; i < 10; i++){
        nextTime = 
    (intMath.round((getRange(getX(),getY(),p.x,p.y)/(20-(3*firePower))));
        time = getTime() + nextTime;
        p = target.guessPosition(time);
    }
    /**Turn the gun to the correct angle**/
    double gunOffset = getGunHeadingRadians() - 
                  (Math.PI/2 - Math.atan2(p.y - getY(), p.x - getX()));
    setTurnGunLeftRadians(normaliseBearing(gunOffset));
}

double normaliseBearing(double ang) {
    if (ang > Math.PI)
        ang -= 2*PI;
    if (ang < -Math.PI)
        ang += 2*Math.PI;
    return ang;
}

public double getrange(double x1,double y1, double x2,double y2) {
    double x = x2-x1;
    double y = y2-y1;
    double h = Math.sqrt( x*x + y*y );
    return h;	
}


	/**
	 * onHitByBullet: What to do when you're hit by a bullet
	 */
	public void onHitByBullet(HitByBulletEvent e) {
		turnLeft(90 - e.getBearing());
	}
	
}