Java：计算立方体的体积和底面积

package org.demo;
 
public class Rect {
	//定义矩形长和宽
	private double l,w;
	Rect(double c,double k){
		l=c;
		w=k;
	}
	//矩形面积
	public double s(){
		return w*l;
	}
class Cube extends Rect {
	private double h;
 
	Cube(double c, double k,double g) {
		// TODO Auto-generated constructor stub
		super(c, k);
		h=g;
	}
	//计算立方体体积
	public double v(){
		return s()*h;
	}
//测试类
public void main(String[] args) {
		Cube cube=new Cube(5, 6,7);
	    System.out.println("底面积为："+cube.s());
	    System.out.println("体积为："+cube.v());
	}
}
}