#include <iostream.h> 
const double pi = 3.14159;
class tank_car {
  public:
    double radius, length;
    tank_car ( ) {radius = 3.5; length = 40.0;}
    tank_car (double r, double l) {radius = r; length = l;}
    double volume ( ) {return pi * radius * radius * length;}
};
main ( ) {
  tank_car t1;              ///
  tank_car t2 (3.5, 50.0);  ///
  cout << "The volume of the default tank car is "
       << t1.volume ( )
       << endl
       << "The volume of the specified tank car is "
       << t2.volume ( )
       << endl;
}