// pstand.cc: the PumpStand class.

#include <iostream.h>
#include "car.h"
#include "pump.h"
#include "pstand.h"

PumpStand::PumpStand (int n) : numPumps (n) {
   if (n < 1) {
      cout << "Error! pump stand needs more than 0 pumps\n";
      return;
   }
   
   pumps = new Pump*[numPumps];
   topPump = numPumps - 1;
   
   for (int p = 0; p < numPumps; p++)
      pumps[p] = new Pump();
}

void PumpStand::releasePump (Pump *p) {
   if (topPump >= numPumps) {
      cout << "Error! attempt to release a free pump?\n";
      return;
   }
   pumps[++topPump] = p;   
}

Pump *PumpStand::takeAvailablePump () {
   if (topPump < 0) {
      cout << "Error! no pump available when needed\n";
      return 0;
   }
   
   return pumps[topPump--];   
}