#include <iostream>
#include "Vector_3d.hpp"

// Compile this file together with Vector_3d.cpp.
//
// This file contains a main() function. A C++ program can
// have only one main() function. If your project already
// contains a main.cpp file, either:
//
//  1. remove main.cpp from the project or build, or
//
//  2. temporarily rename its main() function to old_main().
//
// The second option allows the original demonstration
// program to remain in the project while this program is
// being compiled and run.

int main() {
  // The member variables of Vector_3d are public.
  Vector_3d u{ 3.2, -4.5, 2.1 };

  std::cout << "Initially:" << std::endl;
  std::cout << "u = " << u << std::endl;

  // Consequently, the user can access the member
  // variables directly.
  std::cout << std::endl
            << "The individual components are:" << std::endl;
  std::cout << "u.x_ = " << u.x_ << std::endl;
  std::cout << "u.y_ = " << u.y_ << std::endl;
  std::cout << "u.z_ = " << u.z_ << std::endl;

  // The user can also modify the member variables directly.
  u.x_ = 10.0;
  u.y_ = 20.0;
  u.z_ = 30.0;

  std::cout << std::endl
            << "After modifying the member variables:"
            << std::endl;
  std::cout << "u = " << u << std::endl;

  // In this particular class, allowing direct access to
  // the member variables does not cause an obvious problem.
  //
  // Any three double-precision floating-point values form
  // a valid 3-dimensional vector. There is no relationship
  // between x_, y_, and z_ that must be maintained.
  //
  // This will not be true for all classes. In particular,
  // our Rational and Array classes have conditions that
  // their member variables must satisfy.

  return 0;
}