设计一个CShape基类，由CShape类派生出矩形类CRectangle。再由矩形类CRectangle派生出长方体类CCuboid，设计不属于这些类的Display函数，用来输出CRectangle和CCuboid对象的周长和面积。根据下面的测试程序设计这些类及函数Display。请自行补充所涉及的头文件。

#include <iostream>
using namespace std;

class CShape {
public:
    virtual double area() = 0;
    virtual double perimeter() = 0;
};

class CRectangle : public CShape {
public:
    CRectangle(double l, double w) : length(l), width(w) {}
    double area() override {
        return length * width;
    }
    double perimeter() override {
        return 2 * (length + width);
    }
protected:
    double length;
    double width;
};

class CCuboid : public CRectangle {
public:
    CCuboid(double l, double w, double h) : CRectangle(l, w), height(h) {}
    double volume() {
        return length * width * height;
    }
private:
    double height;
};

void Display(CRectangle& r) {
    cout << "The area of the rectangle is " << r.area() << endl;
    cout << "The perimeter of the rectangle is " << r.perimeter() << endl;
}

void Display(CCuboid& c) {
    cout << "The area of the cuboid is " << c.area() << endl;
    cout << "The perimeter of the cuboid is " << c.perimeter() << endl;
    cout << "The volume of the cuboid is " << c.volume() << endl;
}

int main() {
    CRectangle r(2, 3);
    CCuboid c(2, 3, 4);
    Display(r);
    Display(c);
    return 0;
}