39.cpp

#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

class Box
{
	private:
	double length;
	double width;
	double height;
	 
	public:
	// Constructors
	Box(double lv, double wv, double hv) : length (lv), width (wv), height (hv) {}
	Box(): length (1.0), width (1.0), height (1.0){}		// No-arg constructor
	 
	double volume() const	// Function to calculate the volume
	{ return length*width*height; }
	 
	// Accessors
	double getLength() const { return length; }
	double getWidth() const { return width; }
	double getHeight() const { return height; }
	 
	friend ostream& operator<<(ostream& stream, const Box& box);
};

ostream& operator<<(ostream& stream, const Box& box)
{
	stream << " Box(" << setw(2) << box.length << ","
	<< setw(2) << box.width << ","
	<< setw(2) << box.height << ")";
	return stream;
}

class Carton : public Box
{
	private:
	string material;
	 
	public:
	Carton(const string desc = "Cardboard") : material(desc) {} // Constructor
	void showDetails()
	{
		cout << "\nMaterial = " << material;
//		cout << "\nLength = " << length;
		cout << "\nLength = " << getLength();
//		cout << "\nWidth = " << width;
		cout << "\nWidth = " << getWidth();
//		cout << "\nHeight = " << height;
		cout << "\nHeight = " << getHeight();
		cout << endl;
	}
//	double carton_volume() { return length*width*height; }
};

int main()
{
	// Create a Box object and two Carton objects
	Box box (40.0, 30.0, 20.0);
	Carton carton;
	Carton candyCarton ("Thin cardboard");
	// Check them out - sizes first of all
	cout << "box occupies " << sizeof box << " bytes" << endl;
	cout << "carton occupies " << sizeof carton << " bytes" << endl;
	cout << "candyCarton occupies " << sizeof candyCarton << " bytes" << endl;
	 
	// Now volumes...
	cout << "box volume is " << box.volume() << endl;
	cout << "carton volume is " << carton.volume() << endl;
	cout << "candyCarton volume is " << candyCarton.volume() << endl;
	cout << "candyCarton length is " << candyCarton.getLength() << endl;
	
	carton.showDetails();
	candyCarton.showDetails();	 
	// Uncomment any of the following for an error...
	// box.length = 10.0;
	// candyCarton.length = 10.0;
	return 0;
}