Problem with std::list

[eliza2044]

Hey guys,

I have a problem printing out the contents of a list of objects, with the following code I loop through the list and call the displayInfo() method that it's responsible for printing out the different attributes of the object.
I have tested the displayInfo() method and works fine, however when I'm calling the method when looping through the list I don't gwt the right content.

Please thake a look at the following code and let me know if you see anything wrong.

void displayAircrafts(list <Aircraft>& detectedAircrafts)
{
     cout << "            DISPLAYING ENTRIES            \n";
     cout << "            ==================            \n";
     cout << "There are " << detectedAircrafts.size()<< " aircrafts in the list!\n\n";

     /*loop through the list by using the iterator*/
     list <Aircraft>::const_iterator iAircraft;

     for (iAircraft= detectedAircrafts.begin(); iAircraft != detectedAircrafts.end(); ++iAircraft)
     {
        Aircraft temp = *iAircraft;
        temp.displayInfo();
     }
}

And this is how I add objects in the list, note that this is part of the code. My actual code compiles fine:

newAir=addAircraft(&dummy);
aircrafts.push_back(newAir);

displayAircrafts(aircrafts);

When I try to display the contents stored in the newAir object by calling the displayInfo method (i.e. newAir.displayInfo()) I get the right result, while the displayAircrafts method gives me something that memory addresses and most of the fields are empty.

Thanks in advance,
Liza

[Salem]

Does your Aircraft class define and implement a copy constructor?

[Tom Gunn]

I can't say what the problem is with what you've shown, but the list makes a copy of the object. Check your copy constructor for the Aircraft class.

[eliza2044]

I've been looking to this problem for a while but I'm sure that it is something really stupid but I can't find what it is.

Here's the aircraft.cpp file:

#include "aircraft.h"

Aircraft::Aircraft()
{
    longitude="";
    latitude="";
    altitude="";
    country="";
    flight="";
    code="";
    earliestTime="";
    latestTime="";

    isOnGround=true;
    speed=0.0;
    track=0.0;
    verticalRate=0.0;
}
Aircraft::Aircraft(string& newLongitude, string& newLatitude, string& newAltitude,string& newCountry, string& newFlight, string& newCode, string& newEarliestTime, string& newLatestTime, bool& newBool, double& newSpeed, double& newTrack, double&  newRate)
{
    longitude=newLongitude;
    latitude=newLatitude;
    altitude=newAltitude;
    country=newCountry;
    flight=newFlight;
    code=newCode;
    earliestTime=newEarliestTime;
    latestTime=newLatestTime;

    isOnGround= newBool;
    speed= newSpeed;
    track= newTrack;
    verticalRate= newRate;
}

Aircraft::Aircraft(string newLongitude, string newLatitude, string newAltitude,
        string newCountry, string newFlight, string newCode, string newEarliestTime, string newLatestTime, bool newBool, double newSpeed, double newTrack, double  newRate)
{
    longitude=newLongitude;
    latitude=newLatitude;
    altitude=newAltitude;
    country=newCountry;
    flight=newFlight;
    code=newCode;
    earliestTime=newEarliestTime;
    latestTime=newLatestTime;

    isOnGround= newBool;
    speed= newSpeed;
    track= newTrack;
    verticalRate= newRate;
}

void Aircraft::setAll(string newLongitude, string newLatitude, string newAltitude,
        string newCountry, string newFlight, string newCode, string newEarliestTime, string newLatestTime, bool newBool, double newSpeed, double newTrack, double  newRate)
{
    longitude=newLongitude;
    latitude=newLatitude;
    altitude=newAltitude;
    country=newCountry;
    flight=newFlight;
    code=newCode;
    earliestTime=newEarliestTime;
    latestTime=newLatestTime;

    isOnGround= newBool;
    speed= newSpeed;
    track= newTrack;
    verticalRate= newRate;
}

Aircraft::Aircraft(const Aircraft& orig) {
}

Aircraft::~Aircraft() {
}

//set methods
void Aircraft::setCoords(string newLong, string newLat, string newAlt )
{
    longitude= newLong;
    latitude= newLat;
    altitude= newAlt;
}

void Aircraft::setEarliestTime(string newTime)//the time that the aircraft was first detected
{
    earliestTime=newTime;
}

void Aircraft::setLatestTime(string newTime)
{
    latestTime = newTime;
}

void Aircraft::setCode(string newCode)//this is the uniques aircraft ID, column 3 in the bst file
{
    code=newCode;
}
void Aircraft::setFlight(string newFlight)// column 5
{
    flight = newFlight;
}

void Aircraft::setCountry(string newCountry)//column 6
{
    country=newCountry;
}

void Aircraft::setLong(string newLong) //column 11 in the bst file
{
    longitude = newLong;
}

void Aircraft::setLat(string newLat) // column 10 in the bst file
{
    latitude = newLat;
}

void Aircraft::setAlt(string newAlt) // column 8 and 9 in the bst file (in feet)
{
    altitude= newAlt;
}
void Aircraft::setIsOnGround(bool newBool)
{
    isOnGround=newBool;
}

void Aircraft::setTrack(double newTrack)
{
    track=newTrack;
}

void Aircraft::setSpeed(double newSpeed)
{
    speed=newSpeed;
}

void Aircraft::setVerticalRate(double newRate)
{
    verticalRate=newRate;
}




//get methods
string Aircraft::getCode()
{
    return code;
}

string Aircraft::getFlight()
{
    return flight;
}

string Aircraft::getCountry()
{
    return country;
}

string Aircraft::getLong()
{
    return longitude;
}

string Aircraft::getLat() 
{
    return latitude;
}

string Aircraft::getAlt() 
{
    return altitude;
}

string Aircraft::getEarliestTime()
{
    return earliestTime;
}

string Aircraft::getLatestTime() 
{
    return latestTime;
}

bool Aircraft::getIsOnGround()
{
    return isOnGround;
}

double Aircraft::getTrack()
{
    return track;
}

double Aircraft::getSpeed()
{
    return speed;
}

double Aircraft::getVerticalRate()
{
    return verticalRate;
}

/* OPERATIONS */
void Aircraft::displayInfo()
{
    std::cout << "Displaying Aircraft Information\n";
    std::cout << "-------------------------------\n";
    std::cout << "Longitude:\t" << longitude << "\n";
    std::cout << "Latitude:\t" << latitude << "\n";
    std::cout << "Altitude:\t" << altitude << "\n";
    std::cout << "Country:\t" << country << "\n";
    std::cout << "Callsign:\t" << flight << "\n";
    std::cout << "ModeS add:\t" << code << "\n";
    std::cout << "Earliest Time:\t" << earliestTime << "\n";
    std::cout << "Latest Time:\t" << latestTime << "\n";
    std::cout << "Landed:\t\t" << isOnGround << "\n";
    std::cout << "Speed:\t\t" << speed << "\n";
    std::cout << "Track:\t\t" << track << "\n";
    std::cout << "Vertical Rate:\t" << verticalRate << "\n";
    std::cout << "\n\n\n";
}

[Tom Gunn]

You have a copy constructor, but it doesn't copy anything.

[eliza2044]

Guys thanks for your very quick responses.

I have followed a similar approach for a different project and it worked fine..!

Can you tell me how a copy constructor works because I have no idea?

Thanks in advance..!

[eliza2044]

Thanks guys I sorted it out, I can't believe that I didn't see what was the problem!!!

Thanks a lot for your help!!! ;)

[Tom Gunn]

Thanks guys I sorted it out

That's great! What did you do to fix it?

[eliza2044]

That's great! What did you do to fix it?

Lol changed the copy constructor...
I initially thought that the problem was with the method that was printing out each object's content.

[tag5]

really, i cant say any thing but u must try always to include
using namespace std; as this defines the preprocessor directitive
ok, thankyou.

[eliza2044]

really, i cant say any thing but u must try always to include
using namespace std; as this defines the preprocessor directitive
ok, thankyou.

I will keep that in mind thanks!!! :)

[mvmalderen]

I will keep that in mind thanks!!! :)

No, don't do it, what he says is wrong...