[Qt] Pointer auto-deassignment problem.

[xyliosist]

Hello there.
I've been struggling with this problem for 2 days [~30hours]. I'm writing my master thesis, and I'm stuck with pointers. Below I'll present some sample code. But what's the problem?
I have lots of QVector<myClass*> and when I'm operating on these myClass pointers values sometimes disappear. In sample below it, when I merge two WordClasses, parentClass of one of the words disappears. Don't know why.

Ok. Here are the classes:


----------
class dictionary
{
QVector<word> slowa;
public:
dictionary();
word* addWord();
int size();
word* getWord(int i);
};
---------


word* dictionary::addWord()
{
word nowe;
this->slowa.push_back(nowe);
return &slowa[slowa.size()-1];
}

int dictionary::size()
{
return slowa.size();
}

word* dictionary::getWord(int i)
{
if (i<slowa.size() && i>=0)
return &slowa[i];
return 0;
}



----------


class word
{
QString name;
wordclass *parentClass;
QVector<word*> nextWords;
public:
word();
void setParentClass(wordclass *wc);
wordclass* getParentClass();
void addWord(word *w);
QVector<word*> getWords();
void setName(QString n);
QString getName();
};



word::word()
{
}

void word::setParentClass(wordclass *wc)
{
wordclass *w;
w = wc;
this->parentClass = w;
}

wordclass* word::getParentClass()
{
return parentClass;
}

void word::addWord(word *w)
{
nextWords.push_back(w);
}

QVector<word*> word::getWords()
{
return nextWords;
}

void word::setName(QString n)
{
name = n;
}

QString word::getName()
{
return name;
}



----------



class wordclass
{
QVector<word*> words;
int id;
public:
wordclass(int i=0);
void addWord(word*);
void delWord(word*);
int size();
word* getWord(int i);
QVector<word*> getWords();
int getId();

};


wordclass::wordclass(int i):id(i)
{
words.push_back(0);
}

void wordclass::addWord(word *w)
{
this->words.push_back(w);
w->setParentClass(this);
}

void wordclass:elWord(word *w)
{
this->words.remove(words.indexOf(w));
}

int wordclass::size()
{
return words.size();
}

word* wordclass::getWord(int i)
{
return words[i];
}

QVector<word*> wordclass::getWords()
{
return words;
}

int wordclass::getId()
{
return this->id;
}



----------

class wordclasses
{
QVector<wordclass> wektor;
int internalPointer;
public:
wordclasses();
wordclass* addWordClass();
wordclass* getWordClass(int i);
int size();
void merge(int i,int j);

};


wordclasses::wordclasses()
{
internalPointer = 0;
}

wordclass* wordclasses::addWordClass()
{
wordclass nowa(++internalPointer);
this->wektor.push_back(nowa);
return &wektor.last();
}

int wordclasses::size()
{
return wektor.size();
}

wordclass* wordclasses::getWordClass(int i)
{
if (i<wektor.size() && i>=0)
return &wektor[i];
return 0;
}

void wordclasses::merge(int i, int j)
{
wordclass *i_,*j_;
i_ = getWordClass(i);
j_ = getWordClass(j);
QVector<word*> words;
words = i_->getWords();
for (int z=0;z<words.size();z++)
{
words[z]->setParentClass(j_);
i_->delWord(words[z]);
j_->addWord(words[z]);

}
this->wektor.remove(i);
}




----------


----------

And in mainclass:


word *ptr;
ptr = dict.addWord();
ptr->setName("one");
ptr = dict.addWord();
ptr->setName("two");
ptr = dict.addWord();
ptr->setName("three");
doSomethingWithWord();
initWordClasses();

for (int i=0;i<wordClasses.size();i++)
{
wordclass *wc;
wc = wordClasses.getWordClass(i);
qDebug()<<"WC: "<<QString::number(wc->getId());
QVector<word*> wds;
wds = wc->getWords();
for (int j=0;j<wds.size();j++)
{
//CRASHES HERE. There's no ParentClass.
qDebug()<<"->"<<wds[j]->getName()<<wds[j]->getParentClass()->getId();
}
}




I've no idea what's wrong. I guess it's something with pointer assignment, but couldn't figure out what :/
If in method I do something like this:

{
word *ptr;
ptr = variable.getWordPointer();
myVectorOfWordPointers.push_back(ptr);
}

Then it looks like ptr after execution of method disappears, like a normal variable. <br/>And is it allright to do something like this:


ptr* class::method()
{
return &myInnerVectorOfVars[0];
}


Will it return pointer to the element at position 0 in Vector? Or will it return pointer to variable returned from vector [volatile one].

I'm in deep wood, and don't know what to do :/


Code in tar.gz in attachment.