```/*
*
*  This file is the solution to an exercise problem posed during
*  one of the UW CSE 333 lectures (333exercises).
*
*  333exercises is free software: you can redistribute it and/or modify
*  the Free Software Foundation, either version 3 of the License, or
*  (at your option) any later version.
*
*  333exercises is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU General Public License for more details.
*
*  You should have received a copy of the GNU General Public License
*  along with 333exercises.  If not, see <http://www.gnu.org/licenses/>.
*/

// lec 10 exercise 2

#ifndef _LEC10_EX2_THREEDBOX_H_
#define _LEC10_EX2_THREEDBOX_H_

#include <iostream>
#include "ThreeDPoint.h"

using namespace std;

// A "ThreeDBox" is a class representing a three-dimensional box
// aligned with the axis with right angles.  Internally, we
// represent a ThreeDBox with two ThreeDPoint objects: a and b,
// where a.x_ <= b.x_, a.y_ <= b.y_, a.z_ <= b.z_.
class ThreeDBox {
public:

// Constructors; use initialization lists to initialize.
ThreeDBox() : a_(), b_() {}
ThreeDBox(const ThreeDPoint &a, const ThreeDPoint &b)
: a_(a), b_(b) { }

// Copy constructor.
ThreeDBox(const ThreeDBox &bx);

// Accessors (inlined).
ThreeDPoint get_a() const { return a_; };
ThreeDPoint get_b() const { return b_; };

// Volume.
double Volume() const;

// Tests if self is inside bx.
bool IsInside(const ThreeDBox &bx) const;

// Assignment operator.
ThreeDBox &operator=(const ThreeDBox &pt);

// Override "<<" for std::ostream.
friend ostream &operator<<(ostream &out, const ThreeDBox &pt);

private:
ThreeDPoint a_, b_;
};

#endif  // _LEC10_EX2_THREEDBOX_H_
```