#include <iostream.h>
// Define box_car_volume first:
double box_car_volume (double h, double w, double l) {
  cout << "The value of l inside box_car_volume is "
       << l << endl;
  return h * w * l;
}
// Then, define main:
main ( ) {
  double l = 40.0, volume;
  cout << "The value of l outside box_car_volume is "
       << l << endl;
  volume = box_car_volume (10.5, 9.5, l + 10.0);
  cout << "The volume of a stretched box car is "
       << volume << endl;
  cout << "The value of l outside box_car_volume is still "
       << l << endl;
}