3. C++ struct, cont.

• With set_dimensions() and area() member functions added to
  the Rectangle struct, the main() function can be re-written as follows:

  
  int main()
  {
      Rectangle rect { 20, 10 };
  
      std::cout << "rectangle width: " << rect.width << '\n';
      std::cout << "rectangle height: " << rect.height << '\n';
      std::cout << "rectangle area: " << rect.area() << '\n';
  
      rect.set_dimensions( 44, 33 );
  
      std::cout << "updated rectangle width: " << rect.width << '\n';
      std::cout << "updated rectangle height: " << rect.height << '\n';
      std::cout << "updated rectangle area: " << rect.area() << '\n';
      return 0;
  }