Java问题，怎么求长方体的体积

Question

 class Cuboid { double a; double b;             double h;             double area; public Cuboid(double a, double b,double h){ this.a = a; this.b = b; this.h = h; } public Cuboid() { // TODO Auto-generated constructor stub } double Area(){ area=a*b*h; return area; } }   public class  Test67{    public static void main(String args[]){   Cuboid cuboid = new Cuboid();   double a=12.5,b=5.2,h=2.5;   Cuboid.Cuboid(a,b,h);   System.out.println("长方提体的体积是:"+cuboid.Area());}}这是题目：1. 编程扩展下面的矩形类（Rect）为长方体类（Cuboid），要求增加高度（h）属性，并求出长方体的体积（Volume）。public class Rect {double a;double b; public Rect(double a, double b){this.a = a;this.b = b;}public double Area(){return a * b;}}

Answer 1

public class Rect {
double a;
double b;
double c;
//带三个参数（长宽高）的构造函数
public Rect(double a, double b,double c){
this.a = a;
this.b = b;
this.c = c;
}
public double Area(){
return a * b* c;
}
public static void main(String[] args) {
	Rect r = new Rect(2.1,3.2,4.3);
	System.out.println(r.Area());
}
}