// pstand.h: the PumpStand class, representing the complete collection of
// pumps at the gas station.

class PumpStand {
private:
   Pump ** pumps; // an array of pointers to pumps
   int numPumps;
   int topPump;

public:

   // Constructor: build a PumpStand of numPumps pumps, and make all of
   // them available.
   PumpStand (int n);

   // aPumpIsAvailable: return true/false according to whether at least one
   // pump is free for use.
   int aPumpIsAvailable () { return topPump >= 0; }

   // getNumberOfPumps: return the number of pumps in the pump stand.
   // (This method is needed when statistics are gathered.)
   int getNumberOfPumps () { return numPumps; }

   // releasePump: put pump p back in the stock of available pumps.
   void releasePump (Pump *p);

   // takeAvailablePump: take a pump from the set of free pumps, and return that pump.
   Pump *takeAvailablePump ();
};