```/*
*
*  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

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

using namespace std;

// Copy constructor.
ThreeDBox::ThreeDBox(const ThreeDBox &bx) {
a_ = bx.a_;
b_ = bx.b_;
}

// Volume.
double ThreeDBox::Volume() const {
double vol = 0.0;

vol = b_.get_x() - a_.get_x();
vol *= (b_.get_y() - a_.get_y());
vol *= (b_.get_z() - a_.get_z());
return vol;
}

// Test inside.
bool ThreeDBox::IsInside(const ThreeDBox &bx) const {
if ((bx.a_.get_x() > a_.get_x()) ||
(bx.b_.get_x() < b_.get_x()))
return false;
if ((bx.a_.get_y() > a_.get_y()) ||
(bx.b_.get_y() < b_.get_y()))
return false;
if ((bx.a_.get_z() > a_.get_z()) ||
(bx.b_.get_z() < b_.get_z()))
return false;

return true;
}

// Assignment operator.
ThreeDBox &ThreeDBox::operator=(const ThreeDBox &pt) {
if (this != &pt) {
a_ = pt.a_;
b_ = pt.b_;
}
return *this;
}

// Override "<<" for std::ostream.
ostream &operator<<(ostream &out, const ThreeDBox &pt) {
out << "[ " << pt.a_ << " -- " << pt.b_ << " ]";
return out;
}
```