Copying an QList into a new, sorted QList.

[Thomas Wrobel]

I wish to have a function return a sorted version of a QList. (The QList is of a custom-type called an "arblip")

I have two ideas how to do this;

a) Either I could copy the whole array, and use qSort, returning the copy.
or
b) Iterate though the items in one list, copying them into a new list.

I'm not sure which is the better approach, and having tried both, I can get neither to work. I suspect its because I'm a neewbie and not understanding how to clone an array, or am getting my pointers mixed up, or both.

My attempt at using qsort was basicaly;

bool compareNames(arblip& s1,arblip& s2)
{
  QDateTime temp1=s1.getLastUpdateTime();
  QDateTime temp2=s2.getLastUpdateTime();
 
  return (temp1<temp2);
}
 
QList<arblip> arbliparray::getallblips_orderedbytimestamp(){
 
    //create temp list;
    QList <arblip> orderedarray;
 
    orderedarray=arblipStore;
    qSort(orderedarray.begin(),orderedarray.end(),compareNames);
 
    return orderedarray;
}

bool compareNames(arblip& s1,arblip& s2)
{
  QDateTime temp1=s1.getLastUpdateTime();
  QDateTime temp2=s2.getLastUpdateTime();

  return (temp1<temp2);
}

QList<arblip> arbliparray::getallblips_orderedbytimestamp(){

    //create temp list;
    QList <arblip> orderedarray;

    orderedarray=arblipStore;
    qSort(orderedarray.begin(),orderedarray.end(),compareNames);

    return orderedarray;
}

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Which compiled, but once that part of the code was triggered, exited with a "1073741819" code.
I suspected its probably that = statement.

I had a similar issue with trying method b, this time crashing when I tried to assign a arblip object from one list to another.

...arblip currentblip = *arblip_iterator;
 orderedarray.append(currentblip); ...

...arblip currentblip = *arblip_iterator;
 orderedarray.append(currentblip); ...

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I think my problem is not knowing how to make a complete copy of an object, rather then merely creating a new pointer to it?
I want to return a ordered copy of the list, and for the original list to remain private and untouched.

[bood]

the = should be fine here
I think the problem lies somewhere else
but you should paste more code to see...
I suggest you use qDebug to confirm which statement has caused the crash exactly first

[squidge]

Is there a reason you can't use the tried and tested STL sort? No copy needed, as it'll work on the original, unless you want the copy, of course.

[Thomas Wrobel]

Well, in this case I do want a copy, but I'll bare that in mind in future.

the = should be fine here
I think the problem lies somewhere else
but you should paste more code to see...
I suggest you use qDebug to confirm which statement has caused the crash exactly first

Thanks! I was too busy getting confused with the aspects of the language alien to me, I missed a very stupid mistake earlier.
I was calling the function twice from within a for statement (one for a constBegin, the other for a constEnd). It was no wonder it was crashing.
Simply assigning it to use one copy and it all works.