On 26/04/12 23:51, Andre Somers wrote: > Op 26-4-2012 18:47, Nikos Chantziaras schreef: >> On 26/04/12 19:01, André Somers wrote: >>> Op 23-4-2012 20:44, Nikos Chantziaras schreef: >>>> Then you're not doing what you think you're doing: >>>> >>>> QList< QList<int> > listOfLists; >>>> QList<int> listOfInts; >>>> listOfInts.append(10); >>>> >>>> listOfLists.append(listOfInts); >>>> listOfLists[0][0] = 9; >>>> >>>> qDebug()<< listOfLists[0][0]<< listOfInts[0]; >>>> >>>> You are modifying a copy, so it prints"9 10" instead of"10 10". This: >>>> >>>> listOfLists[0][0] = 9; >>>> >>>> modifies a copy of listOfInts. Also the reverse is true. If you modify >>>> listOfInts, then the copy of it inside listOfLists is not updated. >>>> >>>> "Implicit sharing" means that data is copied when it's modified. It's >>>> not a replacement for pointers. >>>> >>> Not true, in this case. >> I posted code that proves my point. It prints "9 10". You can't argue >> with that one ;-) > The copy is made at the moment you _append_ the list, not at the moment > you're modifying it. That's a big difference. So yes, your code prints > "9 10", and it should! However, the issue was about if you could modify > what's in that nested list. You said: > > Note that with QList< QList<int> > you can't modify the other lists. > You'd only be modifying the copies.
Nope. That was not the issue. The issue was that when you append list A into list B, you can't get to list A because what's inside list B is a copy of A, not A itself. You might want to read again from the first post. _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
