关于#输出#的问题，如何解决？

Question

import java.util.Scanner;

class Rectangle {
    private double length, width;
    public Rectangle (double length,double width){
    super();
    this.length=length;
    this.width=width;
    }
    public Rectangle(double side){
    super();
    this.length=side;
    this.width=side;
    }
    public Rectangle(){
    }
    public double getLength(){
    return length;}
    public void setLength(double length){
    if(length<0)
    {
    System.exit(-2);
    }
    this.length=length;
    }
    public double getWidth(){
    return width;
    }
    public void setWidth(double width){
    if(width<0){
    System.exit(-2);
    }
    this.width=width;
    }
    public double getPerimeter(){
    return 2*(width+length);
    }
    public double getArea(){
    return width*length;
    }

}

public class TestRectangle {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Please enter the length and width of rectangle r1:");
        double length = sc.nextDouble();
        double width = sc.nextDouble();
        System.out.println("Please enter the side length of square r2:");
        double side = sc.nextDouble();

        Rectangle r1 = new Rectangle(length, width);
        Rectangle r2 = new Rectangle(side);
        Rectangle r3 = new Rectangle();

        System.out.printf("The perimeter of r1 is %.2f\n", r1.getPerimeter() );
        System.out.printf("The area of r2 is %.2f\n", r2.getArea() );
        System.out.printf("The perimeter of r3 is %.2f\n", r3.getPerimeter() );

        r3.setLength(r1.getLength());
        r3.setWidth(r2.getWidth());
        System.out.printf("After modification, the area of r3 is %.2f\n", r3.getArea() );

        System.out.println("Please enter the length and width of rectangle r3:");
        double r3_length = sc.nextDouble();
        double r3_width = sc.nextDouble();
        sc.close();
        r3.setLength(r3_length);
        r3.setWidth(r3_width);
        System.out.printf("After modification, the area of r3 is %.2f\n", r3.getArea() );
    }
}

为什么最后一行没有输出呢

Answer 1

有输出