[SOLVED] weird Qrand behaviour

doubitchou

hi,
the use of recommanded qrand works nice when executed in PC or through the nokia simulator, but failed strangely to randomize when executed from the N8 itself.
Clearly : A function return a randomized QList, whereas the same function return an ordered QList each time.

I really don't see what is wrong here.

@
QList <int> Keys_Dialog::RandomKeys ()
{
QList <int> Keys_Set ;
QList <int> RemainingList ;

int MAX_KEYS_NB = 10                 ;           // define the max nr of keys to generate
int RandomValue = 0,  nb_val         ;


nb_val = Keys_Set.count()            ;
for (int i=0; i < MAX_KEYS_NB; i ++)
{
       RemainingList.append (i)      ;
}

while( RemainingList.count () > 0)
{
  RandomValue = (int) (((long) qrand() * RemainingList.count())/ RAND_MAX)  ;

      Keys_Set.append (RemainingList.at(RandomValue))                           ;
      RemainingList.removeAt (RandomValue);
      nb_val = Keys_Set.count()       ;

qDebug() << "Keys_Dialog::RandomKeys : " << Keys_Set ;
}

return Keys_Set                       ;

}@

luca.cossaro

Hi,

I've not tested, but I think this

@RandomValue = (int) (((long) qrand() * RemainingList.count())/ RAND_MAX);@

is always 0

doubitchou

Correct !

This was due to a bad init of the random generator that is lower in the the mobile.

thx a lot.