Weird behavior of QList<T>

[VRonin]

@advtaco said in Weird behavior of QList<T>:

That's the stack trace

Which one is line 55 of cmdhandler.cpp?

I know this is something unbelievably obvious that I'm missing but I just can't see the bug yet

[jsulm]

@advtaco Are you sure you really have roomCount entries in the list? You should check that first.

[advtaco]

@jsulm Yep, i checked that in the debugger

@VRonin That's this line:

 printf(QString("Room #" + QString::number(i) + ", " + building->rooms.at(i).name + "\n\r").toLatin1().data());

[Taz742]

@VRonin @jsulm

@advtaco said in Weird behavior of QList<T>:

#ifndef KROOM_H
#define KROOM_H

#include <QList>
#include <QString>
#include <kswitch.h>
#include <kblind.h>

class kRoom
{
public:
kRoom(QString name);
QList<kSwitch> switches;
QList<kBlind> blinds;
QString name;
void addSwitch(kSwitch newSwitch);
void removeSwitch(int remSwitch);
void addBlind(kBlind newBlind);
void removeBlind(int remBlind);
};

When I used class in other classes I had a problem with the following:
like this

> #include <QList>
> #include <QString>
> #include <kswitch.h>
> #include <kblind.h>

class kSwtich;
class kBlind;

Could this be a problem anyway?

[jsulm]

@Taz742 Sory, I don't follow: what problem do you mean?

[jsulm]

@advtaco Not related to your question: may I ask you why you use printf C function? It makes your code more complex as you need to get char* out of QString. Why not use qDebug for debugging or std::cout for regular std out - you're using C++ not C :-)

[Taz742]

@jsulm undefined refernce (class name).
@advtaco you are using Qt 5.9 yeap?
please check other version if you can.

[VRonin]

I'm speechless... I can only thing of something weird going on in building

ok, let's try with an alternative.
replace

for (int i = 0; i < roomCount; i++)
   {
       printf(QString::number(i).toLatin1().data());
       printf(QString("Room #" + QString::number(i) + ", " + building->rooms.at(i).name + "\n\r").toLatin1().data());
       printf(QString("Switches: " + QString::number(building->rooms.at(i).switches.count()) + "\n\r").toLatin1().data());
       printf(QString("Blinds: " + QString::number(building->rooms.at(i).blinds.count()) + "\n\r").toLatin1().data());
       printf("+---------------------------+\n\r");
   }

with

foreach(const kRoom& singleRoom, building->rooms){
qDebug() << singleRoom.name;
}

[jsulm]

@Taz742 Well, you need to have the class definition somewhere, a forward declaration isn't a definition.

[VRonin]

@jsulm said in Weird behavior of QList<T>:

@advtaco Not related to your question: may I ask you why you use printf C function? It makes your code more complex as you need to get char* out of QString. Why not use qDebug for debugging or std::cout for regular std out - you're using C++ not C :-)

For more infos on this front, see https://stackoverflow.com/questions/3886105/how-to-print-to-console-when-using-qt

[advtaco]

@VRonin The qDebug-Variant works! Still don't understand why the old version doesn't but at least it does something now!

@jsulm @VRonin I am looking into other methods to output now

@Taz742 Yes, I am using Qt 5.9

[Taz742]

@advtaco
The problem was qDebug () or foreach (const kRoom & singleRoom, building-> rooms) ?