Modifying the Airport simulation program in ch. 3 - Thid from the textbook data structures and program design in c++ by Robert L. Kruse

Modification: Print the median waiting time of take-off/departing planes and maximum waiting time of landing/arriving planes.

Just answer with the lines of code to add and where.

Original code from textbook:

#include "../../C/UTILITY.H"

#include "../../C/UTILITY.CPP"

#include "PLANE.H"

#include "PLANE.CPP"

typedef Plane Queue_entry;

#include "../QUEUE/QUEUE.H"

#include "../QUEUE/QUEUE.CPP"

#include "../EXTQUEUE/EXTQUEUE.H"

#include "../EXTQUEUE/EXTQUEUE.CPP"

#include "RUNWAY.H"

#include "RUNWAY.CPP"

#include "../../B/RANDOM.H"

#include "../../B/RANDOM.CPP"

void initialize(int &end_time, int &queue_limit,

double &arrival_rate, double &departure_rate)

/*

Pre:

The user specifies the number of time units in the simulation,

the maximal queue sizes permitted,

and the expected arrival and departure rates for the airport.

Post:

The program prints instructions and initializes the parameters

end_time, queue_limit, arrival_rate, and departure_rate to

the specified values.

Uses: utility function user_says_yes

*/

{

cerr << "This program simulates an airport with only one runway." << endl

<< "One plane can land or depart in each unit of time." << endl;

cerr << "Up to what number of planes can be waiting to land "

<< "or take off at any time? " << flush;

cin >> queue_limit;

cerr << "How many units of time will the simulation run?" << flush;

cin >> end_time;

bool acceptable;

do {

cerr << "Expected number of arrivals per unit time?" << flush;

cin >> arrival_rate;

cerr << "Expected number of departures per unit time?" << flush;

cin >> departure_rate;

if (arrival_rate < 0.0 || departure_rate < 0.0)

cerr << "These rates must be nonnegative." << endl;

else

acceptable = true;

if (acceptable && arrival_rate + departure_rate > 1.0)

cerr << "Safety Warning: This airport will become saturated. " << endl;

} while (!acceptable);

}

void run_idle(int time)

/*

Post:

The specified time is printed with a message that the runway is idle.

*/

{

cout << time << ": Runway is idle." << endl;

}

int main() // Airport simulation program

/*

Pre:

The user must supply the number of time intervals the simulation is to

run, the expected number of planes arriving, the expected number

of planes departing per time interval, and the

maximum allowed size for runway queues.

Post:

The program performs a random simulation of the airport, showing

the status of the runway at each time interval, and prints out a

summary of airport operation at the conclusion.

Uses:

Classes Runway, Plane, Random and

functions run_idle, initialize.

*/

{

int end_time; // time to run simulation

int queue_limit; // size of Runway queues

int flight_number = 0;

double arrival_rate, departure_rate;

initialize(end_time, queue_limit, arrival_rate, departure_rate);

Random variable;

Runway small_airport(queue_limit);

for (int current_time = 0; current_time < end_time; current_time++) { // loop over time intervals

int number_arrivals = variable.poisson(arrival_rate); // current arrival requests

for (int i = 0; i < number_arrivals; i++) {

Plane current_plane(flight_number++, current_time, arriving);

if (small_airport.can_land(current_plane) != success)

current_plane.refuse();

}

int number_departures= variable.poisson(departure_rate); // current departure requests

for (int j = 0; j < number_departures; j++) {

Plane current_plane(flight_number++, current_time, departing);

if (small_airport.can_depart(current_plane) != success)

current_plane.refuse();

}

Plane moving_plane;

switch (small_airport.activity(current_time, moving_plane)) {

// Let at most one Plane onto the Runway at current_time.

case land:

moving_plane.land(current_time);

break;

case take_off:

moving_plane.fly(current_time);

break;

case idle:

run_idle(current_time);

}

}

small_airport.shut_down(end_time);

}

enum Runway_activity {idle, land, take_off};

class Runway {

public:

Runway(int limit);

Error_code can_land(const Plane ¤t);

Error_code can_depart(const Plane ¤t);

Runway_activity activity(int time, Plane &moving);

void shut_down(int time) const;

private:

Extended_queue landing;

Extended_queue takeoff;

int queue_limit;

int num_land_requests; // number of planes asking to land

int num_takeoff_requests; // number of planes asking to take off

int num_landings; // number of planes that have landed

int num_takeoffs; // number of planes that have taken off

int num_land_accepted; // number of planes queued to land

int num_takeoff_accepted; // number of planes queued to take off

int num_land_refused; // number of landing planes refused

int num_takeoff_refused; // number of departing planes refused

int land_wait; // total time of planes waiting to land

int takeoff_wait; // total time of planes waiting to take off

int idle_time; // total time runway is idle

};

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 ¤t)

/*

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 ¤t)

/*

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::activity(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 if (!takeoff.empty()) {

takeoff.retrieve(moving);

takeoff_wait += time - moving.started();

num_takeoffs++;

in_progress = take_off;

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;

}

enum Plane_status {null, arriving, departing};

class Plane {

public:

Plane();

Plane(int flt, int time, Plane_status status);

void refuse() const;

void land(int time) const;

void fly(int time) const;

int started() const;

private:

int flt_num;

int clock_start;

Plane_status state;

};

Plane::Plane(int flt, int time, Plane_status status)

/*

Post: The Plane data members flt_num, clock_start,

and state are set to the values of the parameters flt,

time and status, respectively.

*/

{

flt_num = flt;

clock_start = time;

state = status;

cout << "Plane number " << flt << " ready to ";

if (status == arriving)

cout << "land." << endl;

else

cout << "take off." << endl;

}

Plane::Plane()

/*

Post: The Plane data members flt_num, clock_start,

state are set to illegal default values.

*/

{

flt_num = -1;

clock_start = -1;

state = null;

}

void Plane::refuse() const

/*

Post: Processes a Plane wanting to use Runway, when

the Queue is full.

*/

{

cout << "Plane number " << flt_num;

if (state == arriving)

cout << " directed to another airport" << endl;

else

cout << " told to try to takeoff again later" << endl;

}

void Plane::land(int time) const

/*

Post: Processes a Plane that is landing at the specified time.

*/

{

int wait = time - clock_start;

cout << time << ": Plane number " << flt_num << " landed after "

<< wait << " time unit" << ((wait == 1) ? "" : "s")

<< " in the landing queue." << endl;

}

void Plane::fly(int time) const

/*

Post: Process a Plane that is taking off at the specified time.

*/

{

int wait = time - clock_start;

cout << time << ": Plane number " << flt_num << " took off after "

<< wait << " time unit" << ((wait == 1) ? "" : "s")

<< " in the takeoff queue." << endl;

}

int Plane::started() const

/*

Post: Return the time that the Plane entered the airport system.

*/

{

return clock_start;

}