Problems with compiling. Errors E0413, E0434, C2664, C2440 - c++

Question

I got this source code from our course material but I can't get it to work. The program is a flight simulator. This link might be useful to understand the bigger picture. Starting on page 67. http://brahms.emu.edu.tr/rza/tr3.pdf
These are the errors that Visual Studio gives to me.
Error E0413 no suitable conversion function from "const Plane" to "const Queue_entry" exists. Runaway.cpp lines 32 & 57
Error E0413 no suitable conversion function from "Extended_queue" to "Runway_activity" exists. Runaway.cpp lines 85 & 93
Error E0434 a reference of type "Queue_entry &" (not const-qualified) cannot be initialized with a value of type "Plane". Runaway.cpp line 96.
Error C2664 'Error_code Queue::append(const Queue_entry &)': cannot convert argument 1 from 'const Plane' to 'const Queue_entry &'. Runaway.cpp lines 32 & 57
Error C2664 'Error_code Queue::retrieve(Queue_entry &) const': cannot convert argument 1 from 'Plane' to 'Queue_entry &'. Runaway.cpp lines 85 & 93
Error C2440 '=': cannot convert from 'Extended_queue' to 'Runway_activity'. Runaway.cpp line 96.
Runaway.h
#include "Utility.h"
#include "Extended_queue.h"
#include "Plane.h"
enum Runway_activity { idle, land, takeoff };
class Runway {
public:
Runway(int limit);
Error_code can_land(const Plane& current);
Error_code can_depart(const Plane& current);
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
};
Runaway.cpp
#include "Runway.h"
#include <iostream>
using namespace std;
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::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 = takeoff;
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;
}
Plane.h
#pragma once
#include "Utility.h"
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.cpp
#include "Plane.h"
#include <iostream>
using namespace std;
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 takeoff 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;
}
Extended_queue.h
#pragma once
#include "Queue.h"
class Extended_queue : public Queue {
public:
bool full() const;
int size() const;
void clear();
Error_code serve_and_retrieve(Queue_entry& item);
void print();
};
Extended_queue.cpp
#include "Extended_queue.h"
int Extended_queue::size() const
/*
Post: Return the number of entries in the Extended_queue.
*/
{
return count;
}
bool Extended_queue::full() const
{
return maxqueue == this->count;
}
void Extended_queue::clear()
{
this->count = 0;
this->front = 0;
this->rear = maxqueue - 1;
}
Error_code Extended_queue::serve_and_retrieve(Queue_entry& item)
{
if (count <= 0) return underflow;
item = entry[front];
count--;
front = ((front + 1) == maxqueue) ? 0 : (front + 1);
return success;
}
void Extended_queue::print()
{
for (int i = 0, j = front;
i < this->count; i++, j = ((j + 1) == maxqueue) ? 0 : (j + 1))
cout << this->entry[j] << ' ';
cout << endl;
}
Queue.h
#include "Utility.h"
typedef char Queue_entry;
const int maxqueue = 1000; // small value for testing
class Queue {
public:
Queue();
bool empty() const;
Error_code serve();
Error_code append(const Queue_entry& item);
Error_code retrieve(Queue_entry& item) const;
protected:
int count;
int front, rear;
Queue_entry entry[maxqueue];
};
Queue.cpp
#include "Queue.h"
Queue::Queue()
/*
Post: The Queue is initialized to be empty.
*/
{
count = 0;
rear = maxqueue - 1;
front = 0;
}
bool Queue::empty() const
/*
Post: Return true if the Queue is empty, otherwise return false.
*/
{
return count == 0;
}
Error_code Queue::append(const Queue_entry& item)
/*
Post: item is added to the rear of the Queue. If the Queue is full
return an Error_code of overflow and leave the Queue unchanged.
*/
{
if (count >= maxqueue) return overflow;
count++;
rear = ((rear + 1) == maxqueue) ? 0 : (rear + 1);
entry[rear] = item;
return success;
}
Error_code Queue::serve()
/*
Post: The front of the Queue is removed. If the Queue
is empty return an Error_code of underflow.
*/
{
if (count <= 0) return underflow;
count--;
front = ((front + 1) == maxqueue) ? 0 : (front + 1);
return success;
}
Error_code Queue::retrieve(Queue_entry& item) const
/*
Post: The front of the Queue retrieved to the output
parameter item. If the Queue is empty return an Error_code of underflow.
*/
{
if (count <= 0) return underflow;
item = entry[front];
return success;
}
Utility.h
#pragma once
#include <iostream>
using namespace std;
enum Error_code {
success, fail, utility_range_error, underflow, overflow, fatal, not_present,
duplicate_error, entry_inserted, entry_found, internal_error
};
bool user_says_yes();
Utility.cpp
#include "Utility.h"
#include <iostream>
using namespace std;
bool user_says_yes()
{
int c;
bool initial_response = true;
do { // Loop until an appropriate input is received.
if (initial_response)
cout << " (y,n)? " << flush;
else
cout << "Respond with either y or n: " << flush;
do { // Ignore white space.
c = cin.get();
} while (c == '\n' || c == ' ' || c == '\t');
initial_response = false;
} while (c != 'y' && c != 'Y' && c != 'n' && c != 'N');
return (c == 'y' || c == 'Y');
}
Main.cpp
#include "Random.h"
#include "Plane.h"
#include "Runway.h"
#include "Utility.h"
#include <iostream>
using namespace std;
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;
}
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
*/
{
cout << "This program simulates an airport with only one runway." << endl
<< "One plane can land or depart in each unit of time." << endl;
cout << "Up to what number of planes can be waiting to land "
<< "or take off at any time? " << flush;
cin >> queue_limit;
cout << "How many units of time will the simulation run?" << flush;
cin >> end_time;
bool acceptable;
do {
cout << "Expected number of arrivals per unit time?" << flush;
cin >> arrival_rate;
cout << "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);
}
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 takeoff:
moving_plane.fly(current_time);
break;
case idle:
run_idle(current_time);
}
}
small_airport.shut_down(end_time);
}
I have tried to solve this for two days now so I really need help. Thanks in advance!

Answer 1

You're trying to fix a Plane inside a char sized hole. The compiler is telling you that it doesn't know how to convert a Plane to a Queue_entry which you define to be a char.
If you want it to be able to your Plane should inherit from Queue_entry. You should familiarize yourself with polymorphism, as it seems like that's what you're going for.
But even then it's likely that things won't work out as it does not seem like you have fully considered the memory allocation of your objects. If you want to put objects in a vector they will be allocated by the vector as necessary. This means you cannot have a vector of interfaces, as the object implementing the interface could have any size. What you could do instead is have a vector of unique_ptr<Queue_entry>.