runway.cpp

飞机场模拟系统

#include "Runway.h"

Runway::Runway(int limit)
/*
Post:  The Runway data members are initialized to record no
       prior Runway use and to record the limit on queue sizes.
*/

{
   queue_limit = limit;
   num_land_requests = num_takeoff_requests = 0;
   num_landings = num_takeoffs = 0;
   num_land_refused = num_takeoff_refused = 0;
   num_land_accepted = num_takeoff_accepted = 0;
   land_wait = takeoff_wait = idle_time = 0;
}


Error_code Runway::can_land(const Plane &current)
/*
Post:  If possible, the Plane current is added to the
       landing Queue; otherwise, an Error_code of overflow is
       returned. The Runway statistics are updated.
Uses:  class Extended_queue.
*/

{
   Error_code result;
   if (landing.size() < queue_limit)
      result = landing.append(current);
   else
      result = fail;
   num_land_requests++;

   if (result != success)
      num_land_refused++;
   else
      num_land_accepted++;

   return result;
}


Error_code Runway::can_depart(const Plane &current)
/*
Post:  If possible, the Plane current is added to the
       takeoff Queue; otherwise, an Error_code of overflow is
       returned. The Runway statistics are updated.
Uses:  class Extended_queue.
*/

{
   Error_code result;
   if (takeoff.size() < queue_limit)
      result = takeoff.append(current);
   else
      result = fail;
   num_takeoff_requests++;
   if (result != success)
      num_takeoff_refused++;
   else
      num_takeoff_accepted++;

   return result;
}


Runway_activity Runway::canland(int time, Plane &moving)
/*
Post:  If the landing Queue has entries, its front
       Plane is copied to the parameter moving
       and a result  land is returned. Otherwise,
       if the takeoff Queue has entries, its front
       Plane is copied to the parameter moving
       and a result  takeoff is returned. Otherwise,
       idle is returned. Runway statistics are updated.
Uses:  class Extended_queue.
*/

{
   Runway_activity in_progress;
   
   if (!landing.empty()) {
      landing.retrieve(moving);
      land_wait += time - moving.started();
      num_landings++;
      in_progress = land;
      landing.serve();
   }

   else {
      idle_time++;
      in_progress = idle;
   }
   return in_progress;
}


Runway_activity Runway::canfly(int time, Plane &moving){

 Runway_activity in_progress;            
  if (!takeoff.empty()) {
      takeoff.retrieve(moving);
      takeoff_wait += time - moving.started();
      num_takeoffs++;
      in_progress = fly;
      takeoff.serve();
   }
  else {
      idle_time++;
      in_progress = idle;
   }
   return in_progress;
   
}  


void Runway::shut_down(int time) const
/*
Post: Runway usage statistics are summarized and printed.
*/

{
   cout << "Simulation has concluded after " << time << " time units." << endl
        << "Total number of planes processed "
        << (num_land_requests + num_takeoff_requests) << endl
        << "Total number of planes asking to land "
        << num_land_requests << endl
        << "Total number of planes asking to take off "
        << num_takeoff_requests << endl
        << "Total number of planes accepted for landing "
        << num_land_accepted << endl
        << "Total number of planes accepted for takeoff "
        << num_takeoff_accepted << endl
        << "Total number of planes refused for landing "
        << num_land_refused << endl
        << "Total number of planes refused for takeoff "
        << num_takeoff_refused << endl
        << "Total number of planes that landed "
        << num_landings << endl
        << "Total number of planes that took off "
        << num_takeoffs << endl
        << "Total number of planes left in landing queue "
        << landing.size() << endl
        << "Total number of planes left in takeoff queue "
        << takeoff.size() << endl;
   cout << "Percentage of time runway idle "
        << 100.0 * (( float ) idle_time) / (( float ) time) << "%" << endl;
   cout << "Average wait in landing queue "
        << (( float ) land_wait) / (( float ) num_landings) << " time units";
   cout << endl << "Average wait in takeoff queue "
        << (( float ) takeoff_wait) / (( float ) num_takeoffs)
        << " time units" << endl;
   cout << "Average observed rate of planes wanting to land "
        << (( float ) num_land_requests) / (( float ) time)
        << " per time unit" << endl;
   cout << "Average observed rate of planes wanting to take off "
        << (( float ) num_takeoff_requests) / (( float ) time)
        << " per time unit" << endl;
}

/*************************************************************************/