QHash <int, class*>

Hi,

I started playing with QHash, but I cant make hashPersons function to enumerate all keys and value since its crashing and I don't know why, please help :(

Code:

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class Person
{
 
public:
  Person( QString name, QString number );
 
  QString m_name, m_number;
};
 
Person::Person( QString name, QString number ) : m_name( name ), m_number( number ) {}
 
void hashPersons()
{
 
QHash<int, Person*> hash;
hash[12] = new Person( "Anders", "8447070" );
hash[20] = new Person( "Micke", "7728433" );
 
QHashIterator<int, Person*> i(hash);
 
  while (i.hasNext()) {
 
      qDebug()<<i.key();
      Person *per = i.value();
 
      qDebug()<< "Name: " << per->m_name << "Number: "<<per->m_number;
      i.next();
  }
    hash.clear();
}

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also if I call hash.clear() at the end do I need to delete the value first or clear() will take care of it ?

You need to call i.next() before taking the value with i.value() (btw. its in the first example in QHashIterator documentation):

Code:

---

while (i.hasNext()) {
      i.next();
      qDebug()<<i.key();
      Person *per = i.value();
      if( per ){ // better check before dereferencing a pointer
          qDebug()<< "Name: " << per->m_name << "Number: "<<per->m_number;
      }
  }

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Quote:

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also if I call hash.clear() at the end do I need to delete the value first or clear() will take care of it ?

---

Yes you need to delete allocated values yourself, QHash does not know what kind of data you keep inside it.

hash.clear(): See qDeleteAll() for convenience.