计算矩形和圆形的面积和周长(java)

package exe02;
import java.util.Scanner; 
/*name:Excise1                   功能：计算矩形和圆形的面积和周长
 */
public class second1 {
	public static void main(String[] args) {
	   Scanner sc = new Scanner(System.in);
	   Rectangle re = new Rectangle();
	   System.out.print("请输入矩形的长和宽:");
	   
	   double x = sc.nextDouble();
	   double y = sc.nextDouble();
       while(x<y||x<0||y<0){
    	    System.out.print("输入错误！请重新输入矩形的长和宽:");
    	    x = sc.nextDouble();
    	    y = sc.nextDouble();
	   }
    	   re.setx(x);
    	   re.sety(y);
    	   re.printf();
	   Circle c = new Circle();
	   System.out.print("请输入圆的半径:");
	   
	   double r = sc.nextDouble();
	   while(r<0){
		   System.out.print("输入错误！请输入圆的半径:");
		   r = sc.nextDouble();
	   }
	   c.setr(r);
	   c.printf();
	   sc.close();
	}
}
//定义一个抽象类
abstract class shape{
	//声明变量长，宽，半径
	private double x;
	private double y;
	private double r;
	
	public double getx() {
		return x;
	}

	public void setx(double x) {
		this.x = x;
	}

	public double gety() {
		return y;
	}

	public void sety(double y) {
		this.y = y;
	}

	public double getr() {
		return r;
	}

	public void setr(double r) {
		this.r = r;
	}

	
}

class Rectangle extends shape{
	double area;
	public void Area() {
		area = getx() * gety();	
	}
	double perimeter;
	public void Perimeter() {
		perimeter = 2*(getx() + gety());	
	}
	public void printf() {
		Area();
		Perimeter();
		System.out.println("矩形的面积为:"+area);
		System.out.println("矩形的周长为:"+perimeter);
	}
}

class Circle extends shape{
	double area;
	public void Area() {
		area = Math.PI * getr()*getr();             //因为PI为double类型
	}
	double perimeter;
	public void Perimeter() {
		perimeter = 2*Math.PI*getr();
	}
	public void printf() {
		Area();
		Perimeter();
		System.out.println("圆形的面积为:"+area);
		System.out.println("圆形的周长为:"+perimeter);
	}
}