public class Circle {

public static double calculateArea(double radius) {

double result = Math.PI * radius * radius;

return result;

}

public static double calculateArea2(double radius) {

return Math.PI * radius * radius;

}

public static double distance

(double x1, double y1, double x2, double y2) {

double dx = x2 - x1;

double dy = y2 - y1;

System.out.println("dx is " + dx);

System.out.println("dy is " + dy);

return 0.0;

}

public static double distance2

(double x1, double y1, double x2, double y2) {

double dx = x2 - x1;

double dy = y2 - y1;

double dsquared = dx * dx + dy * dy;

System.out.println("dsquared is " + dsquared);

return 0.0;

}

public static double distance3

(double x1, double y1, double x2, double y2) {

double dx = x2 - x1;

double dy = y2 - y1;

double dsquared = dx * dx + dy * dy;

double result = Math.sqrt(dsquared);

return result;

}

public static double circleArea

(double xc, double yc, double xp, double yp) {

double radius = distance(xc, yc, xp, yp);

double area = calculateArea(radius);

return area;

}

public static double calculateArea

(double xc, double yc, double xp, double yp) {

return calculateArea(distance(xc, yc, xp, yp));

}

public static void main(String[] args) {

System.out.println("calculateArea");

System.out.println(calculateArea(3.0));

System.out.println("calculateArea2");

System.out.println(calculateArea2(3.0));

System.out.println("distance");

System.out.println(distance(1.0, 2.0, 4.0, 6.0));

System.out.println("distance2");

System.out.println(distance2(1.0, 2.0, 4.0, 6.0));

System.out.println("distance3");

System.out.println(distance3(1.0, 2.0, 4.0, 6.0));

System.out.println("circleArea");

System.out.println(circleArea(1.0, 2.0, 4.0, 6.0));

System.out.println("calculateArea with 4 doubles");

System.out.println(calculateArea(1.0, 2.0, 4.0, 6.0));

}

}