定义一个圆，求圆的面积

TestCircle .java

class Point {private double x;private double y;Point(double x1, double y1) { x = x1; y = y1;}public double getX() { return x; }public double getY() { return y; }public void setX(double i) { x = i; }public void setY(double i) { y = i; }
}class Circle {private Point o; //圆心private double radius;  //半径Circle(Point p, double r) {o = p; radius = r;}Circle(double r) {o = new Point(0.0, 0.0);radius = r;}boolean contains(Point p) {double x = p.getX() - o.getX();double y = p.getY() - o.getY();if(x*x + y*y > radius * radius) return false;else return true;}public void setO(double x, double y) {o.setX(x); o.setY(y);}public Point getO() { return o; }public double getRadius() { return radius;}public void setRadius(double r) { radius = r;}public double area() { //求圆的面积return 3.14 * radius * radius;}
}public class TestCircle {public static void main(String args[]) {Circle c1 = new Circle(new Point(1.0,2.0), 2.0);Circle c2 = new Circle(5.0);System.out.println("c1:("+c1.getO().getX()+","+c1.getO().getY()+"),"+c1.getRadius());    //c1:(1.0,2.0),2.0System.out.println("c2:("+c2.getO().getX()+","+c2.getO().getY()+"),"+c2.getRadius());//c2:(0.0,0.0),5.0System.out.println("c1 area = "+c1.area());//c1 area = 12.56System.out.println("c1 area = "+c2.area());//c1 area = 78.5c1.setO(5,6);c2.setRadius(9.0);System.out.println("c1:("+c1.getO().getX()+","+c1.getO().getY()+"),"+c1.getRadius());//c1:(5.0,6.0),2.0System.out.println("c2:("+c2.getO().getX()+","+c2.getO().getY()+"),"+c2.getRadius());//c2:(0.0,0.0),9.0System.out.println("c1 area = "+c1.area());//c1 area = 12.56System.out.println("c1 area = "+c2.area());//c1 area = 254.34Point p1 = new Point(5.2, 6.3);System.out.println(c1.contains(p1));//trueSystem.out.println(c1.contains(new Point(10.0,9.0)));//false}
}