Java 构造方法重载

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;
    private double radius;

    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() {
        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());
        System.out.println("c2:("+c2.getO().getX()
            +","+c2.getO().getY()+"),"+c2.getRadius());
        System.out.println("c1 area = "+c1.area());
        System.out.println("c1 area = "+c2.area());
        c1.setO(5,6);
        c2.setRadius(9.0);
        System.out.println("c1:("+c1.getO().getX()+","
            +c1.getO().getY()+"),"+c1.getRadius());
        System.out.println("c2:("+c2.getO().getX()+","
            +c2.getO().getY()+"),"+c2.getRadius());
        System.out.println("c1 area = "+c1.area());
        System.out.println("c1 area = "+c2.area());

        Point p1 = new Point(5.2, 6.3);
        System.out.println(c1.contains(p1));
        System.out.println(c1.contains(new Point(10.0,9.0)));
    }
}

课件： 构造方法重载.pdf