A class with a destructor

#if !defined VolumesH
#define VolumesH

namespace Volumes
{
class TBox
{
public:
    TBox(double L = 0, double H = 0, double W = 0);
    TBox(const TBox &Box);
    ~TBox();

    void   setLength(const double L) { Length = (L <= 0) ? 0 : L; }
    double getLength() const { return (Length < 0) ? 0 : Length; } 
    void   setHeight(const double H) { Height = (H <= 0) ? 0 : H; }
    double getHeight() const { return (Height < 0) ? 0 : Height; } 
    void   setWidth(const double W)  { Width  = (W <= 0) ? 0 : W; }
    double getWidth() const  { return (Width < 0) ? 0  : Width; }
    void   setDimensions(const double L, const double H, const double W);

    double Area() const;
    double Volume() const;

    TBox Add(const double Value);
    TBox Sub(const double Value);
    TBox Mul(const double Value);
    TBox Div(const double Value);
    TBox Add(const TBox& B);

private:
    double Length;
    double Height;
    double Width;
};
}

#endif	// VolumesH

#include "Volumes.h"

namespace Volumes
{
TBox::TBox(double L, double H, double W)
	: Length(L), Height(H), Width(W)
{
}

TBox::TBox(const TBox &Box)
	: Length(Box.Length),
      Height(Box.Height),
	  Width(Box.Width)
{
}

TBox::~TBox()
{
}

void TBox::setDimensions(const double L, const double H, const double W)
{
	setLength(L);
	setHeight(H);
	setWidth(W);
}

double TBox::Area() const
{
	return 2 * ( ( getLength() * getHeight()) +
		         ( getHeight() * getWidth() ) +
		         ( getLength() * getWidth() ) );
}

double TBox::Volume() const
{
    return getLength() * getHeight() * getWidth();
}

TBox TBox::Add(const double d)
{
	TBox Box;

	Box.Length = Length + d;
	Box.Height = Height + d;
	Box.Width  = Width  + d;

	return Box;
}

TBox TBox::Sub(const double d)
{
	TBox Box;

	Box.Length = Length - d;
	Box.Height = Height - d;
	Box.Width  = Width  - d;

	return Box;
}

TBox TBox::Mul(const double d)
{
	TBox Box;

	Box.Length = Length * d;
	Box.Height = Height * d;
	Box.Width  = Width  * d;

	return Box;
}

TBox TBox::Div(const double d)
{
	if( d == 0 )
		return TBox(0.00, 0.00, 0.00);
	else
	{
		TBox Box;

		Box.Length = Length / d;
		Box.Height = Height / d;
		Box.Width  = Width  / d;

		return Box;
	}
}

TBox TBox::Add(const TBox& Box)
{
	TBox NewBox;

	NewBox.Length = NewBox.Length + Box.Length;
	NewBox.Height = NewBox.Height + Box.Height;
	NewBox.Width  = NewBox.Width  + Box.Width;

	return NewBox;
}

}    // namespace Volumes

#include <iostream>
#include <iomanip>
#include "Volumes.h"

using namespace std;
using namespace Volumes;

void GetDimensions(TBox *Box)
{
    double L, H, W;

    cout << "Specify the dimensions of the box\n";
    cout << "Length: "; cin >> L;
    cout << "Height: "; cin >> H;
    cout << "Width:  "; cin >> W;

    Box->setDimensions(L, H, W);
}

void ShowProperties(const TBox *Box)
{
    cout << "\nBox Properties";
    cout << setiosflags(ios::fixed) << setprecision(2);
    cout << "\nLength = " << Box->getLength();
    cout << "\nHeight = " << Box->getHeight();
    cout << "\nWidth  = " << Box->getWidth();
    cout << "\nArea   = " << Box->Area();
    cout << "\nVolume = " << Box->Volume() << "\n";
}

int main()
{
    TBox Box(6.42, 2.84, 4.56);

    cout << "Box Examples";
    Box = Box.Sub(2.15);

    ShowProperties(&Box);

    return 0;
}