Java、Circle2D类

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                                Circle2D
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-x: double
-y: double
-radius: double
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+Circle2D()
+Circle2D(x: double, y: double, radius: double)
+getArea(): double
+getPerimeter(): double
+contains(x: double, y: double): boolean
+contains(circle: Circle2D): boolean
+overlaps(circle: Circle2D): boolean
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package pack2;

import javafx.geometry.Point2D;

public class Circle2D {
	private double x, y;	//x、y坐标
	private double radius;	//半径
	
	
	public Circle2D() {
		this(0, 0, 1);
	}
	
	
	public Circle2D(double x, double y, double radius) {
		this.radius = radius;
		this.x = x;
		this.y = y;
	}
	
	
	public double getArea() {
		return Math.PI * Math.pow(radius, 2);
	}
	
	
	public double getPerimeter() {
		return 2 * Math.PI * radius;
	}
	
	
	public boolean contains(double x, double y) {
		return Math.sqrt(Math.pow(this.x - x, 2) + Math.pow(this.y - y, 2)) <= radius;
	}
	
	
	public boolean contains(Circle2D circle) {
		return contains(circle.getX(), circle.getY()) && circle.getRadius() < radius;
	}
	
	
	public boolean overlaps(Circle2D circle) {
		double distance = new Point2D(x, y).distance(circle.getX(), circle.getY());
		return distance <= this.radius + circle.getRadius();
	}

	@Override	
	public String toString() {
		return "X: " + x + "nY: " + y + "nRadius: " + radius;
	}
	
	public double getX() {
		return x;
	}

	public double getY() {
		return y;
	}

	public double getRadius() {
		return radius;
	}
	
//——————————————————————————————————————————————————————————
	public static void main(String[] args) {
		Circle2D c1 = new Circle2D(2, 2, 5.5);
		
		System.out.println(c1);
		System.out.println("Area of c1: " + c1.getArea() + 
							"nPerimeter: " + c1.getPerimeter());
		System.out.println("Is (3, 3) contained in c1? " + c1.contains(3, 3));
		System.out.println("Is circle(4, 5, 10.5) contained in c1? " + c1.contains
                    (new Circle2D(4, 5, 10.5)));
		System.out.println("Is c1 overlaping circle(3, 5, 2.3)? " + c1.overlaps
                    (new Circle2D(3, 5, 2.3)));
	}
}