[Qt-interest] Problem with qSort and QObjects

[Florian VICHOT]

Sorry just realised I didn't really answer your second question.

> 1) What I need to do to get the QObject version working? qSort docs
> say that the items need to implement operator<(), but clearly that is
> not enough.

BTW, using QObject by value is a bad idea. I gave the fix to make it
work, but it's not a good idea in most cases. If you copy QObject using
the methods I gave you, it won't copy along signal/slot connections,
etc, since QObject(const QObject& o) is not called.

> 2) Is it possible to overload the operator<() this way (using
> pointers) and use it with qSort?
>     bool operator<(const Account * other ) const;
> My app actually stores pointers to objects (extending QObject) in the
> QList that I want to sort, so will it be possible at all?

No you can't do that. What you would need is :

bool operator<(const Account * a, const Account * b ) {...}

but C++ needs at least one class or native type (non-pointers) argument
in an operator overloading prototype. So the prototype above is not valid.

But you can also use the qSort version that takes three arguments:
void qSort ( RandomAccessIterator begin, RandomAccessIterator end,
LessThan lessThan )

and provide your own "lessThan" function to sort. Something like that:

bool my_less_than(const Account * a, const Account * b )
{
  return (*a < *b);
}

Use it with qSort(list.begin(), list.end(), &my_less_than); and voilà.

Florian