求助，关于继承类的设计与实现java

[weixin_45038258]

继承类的设计与实现，一个矩形类，正方形类，长方形类，还有一个测试类

[Yeva ]

/**
 * 矩形类，包含长宽，计算面积方法*/
public class Rectangle {
	double length,width;
	
	public double computeArea() {
		return length*width;
	}
	
	
	public double getLength() {
		return length;
	}

	public void setLength(double length) {
		this.length = length;
	}

	public double getWidth() {
		return width;
	}

	public void setWidth(double width) {
		this.width = width;
	}
	
}

/**
 * 正方形类，面积方法重写*/
public class Square extends Rectangle{
	@Override
	public double computeArea() {
		return length*length;
	}
}

/**
 * 长方体类， 有长宽高，计算体积方法*/
public class Cuboid extends Rectangle{
	double hight;

	public double getHight() {
		return hight;
	}

	public void setHight(double hight) {
		this.hight = hight;
	}

	public double computeVolume() {
		return length*width*hight;
	}
}

/**
 * 测试类*/
public class Test {
	public static void main(String[] args) {
		Cuboid cuboid = new Cuboid();
		cuboid.setLength(3.5);
		cuboid.setWidth(2.7);
		cuboid.setHight(2);
		System.out.println("长方体底面积："+cuboid.computeArea());
		System.out.println("长方体体积："+cuboid.computeVolume());
		
		Square square = new Square();
		square.setLength(3.5);
		System.out.println("正方形面积："+square.computeArea());
	}
}