// TakeOffQueue class

// TakeOffQueue represents the queue of the planes which are waiting to take off
// This class is derived from the abstract class EventQueue. It implements the
// draw function, which draws out the takeoff queue on the runway. 

#ifndef TAKEOFFQUEUE_H
#define TAKEOFFQUEUE_H

#include "EventQueue.h"

// two constants which are used for drawing out the queue of the planes

// distance between the x-coordinates of the two planes
const int DISTANCE_BETWEEN_PLANES = 40;
const int DISPLAY_OCCUPIED_BY_TAKEOFF_QUEUE = 125;

class TakeOffQueue : public EventQueue {
public:
	// draws the takeoff queue on the display screen
	virtual void draw ();

	// the enqueue for the takeoff queue has to do two tasks.
	// 1. add the event e to the queue
	// 2. assign proper values to the x and y coordinates of the aircraft
	//    object associated with the event e, so that when the queue is 
	//    draw on the display screen, the plane gets displayed in correct position
	// For doing task 1, this function invokes the EventQueue::enqueue function
	// It provides implementation for task 2
	virtual void enqueue (Event *e);

	// the dequeue (like the enqueue above) has two tasks to do
	// 1. remove the element at the head of the queue
	// 2. update the x coordinates of the aircraft objects associated with
	//    the remaining events in the queue.
	// For doing task 1, this function invokes the EventQueue::dequeue function
	// It provides implementation for task 2
	virtual Event* dequeue ();
};

#endif