用java编程求长方形和正方形的面积

/**
*
* @author 摆渡凌云
*/
public class Main {

//应用举例
public static void main(String[] args) {

Rectangle rect = new Rectangle(13,34);
Rectangle square = new Rectangle(13);
System.out.println("长为: " + rect.getLength() +" 宽为:"+rect.getWidth() +" 的长方形面积为:" + rect.getArea());
System.out.println("边长为:" + square.getLength() +" 的正方形面积为:"+square.getArea());

//静态方法调用
System.out.println("长方形的面积" + Rectangle.getArea(23,34));
}
}

//长方形（正方形）类
class Rectangle {

private double length = 0.0; //长
private double width = 0.0; //宽

public double getLength() {
return length;
}

public double getWidth() {
return width;
}

//构造长方形
public Rectangle(doubl