g++ -g -Wall -c Reservoir.cpp
g++ -Wall -g -o hydrosim main.o Canal.o Reservoir.o
Reservoir.o: In function `FillReservoir::initialize()':
/home/it02/feld0091/csci3081/project/project2/Iteration2/Reservoir.cpp:293: undefined reference to `FillReservoir::init_reserve_volume'
/home/it02/feld0091/csci3081/project/project2/Iteration2/Reservoir.cpp:293: undefined reference to `FillReservoir::reserve_volume'
collect2: ld returned 1 exit status
make: *** [hydrosim] Error 1


in Reservoir.cpp

Constructor...
FillReservoir::FillReservoir(std::string _name, double capacity,
                         double minimum_volume, double required_volume):
  MinimumVolumeReservoir(_name, capacity, minimum_volume, required_volume)
{
}


void FillReservoir::initialize()
{
  reserve_volume = init_reserve_volume; <----Line that gives Linker error. 
}

in Reservoir.h

class FillReservoir: public MinimumVolumeReservoir {
public:
  FillReservoir(std::string _name, double capacity,
                double minimum_volume, double required_volume);
  virtual std::string check(std::ostream& out);
  virtual void print_initial(std::ostream& out) const;
  virtual void initialize();
  static void set_reserve_volume(double volume);
  static double get_reserve_volume();
private:
  static double reserve_volume, init_reserve_volume;
};