Viadeo Twitter Google Bookmarks ! Facebook Digg del.icio.us MySpace Yahoo MyWeb Blinklist Netvouz Reddit Simpy StumbleUpon Bookmarks Windows Live Favorites 
Logo Documentation Qt ·  Page d'accueil  ·  Toutes les classes  ·  Classes principales  ·  Annotées  ·  Classes groupées  ·  Modules  ·  Fonctions  · 

QLinkedList::const_iterator Class Reference
[QtCore module]

The QLinkedList::const_iterator class provides an STL-style const iterator for QLinkedList. More...

 #include <QLinkedList>

Inherited by Q3ValueListConstIterator.

Public Functions


Detailed Description

The QLinkedList::const_iterator class provides an STL-style const iterator for QLinkedList.

QLinkedList features both STL-style iterators and Java-style iterators. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity.

QLinkedList<T>::const_iterator allows you to iterate over a QLinkedList<T>. If you want modify the QLinkedList as you iterate over it, you must use QLinkedList::const_iterator instead. It is generally good practice to use QLinkedList::const_iterator on a non-const QLinkedList as well, unless you need to change the QLinkedList through the iterator. Const iterators are slightly faster, and can improve code readability.

The default QLinkedList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a function like QLinkedList::constBegin(), QLinkedList::constEnd(), or QLinkedList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list:

 QLinkedList<QString> list;
 list.append("January");
 list.append("February");
 ...
 list.append("December");

 QLinkedList<QString>::const_iterator i;
 for (i = list.constBegin(); i != list.constEnd(); ++i)
     cout << *i << endl;

STL-style iterators can be used as arguments to generic algorithms. For example, here's how to find an item in the list using the qFind() algorithm:

 QLinkedList<QString> list;
 ...
 QLinkedList<QString>::iterator it = qFind(list.constBegin(),
                                           list.constEnd(), "Joel");
 if (it != list.constEnd())
     cout << "Found Joel" << endl;

Multiple iterators can be used on the same list. If you add items to the list, existing iterators will remain valid. If you remove items from the list, iterators that point to the removed items will become dangling iterators.

See also QLinkedList::iterator and QLinkedListIterator.


Member Function Documentation

const_iterator::const_iterator ()

Constructs an uninitialized iterator.

Functions like operator*() and operator++() should not be called on an uninitialized iterartor. Use operator=() to assign a value to it before using it.

See also QLinkedList::constBegin() and QLinkedList::constEnd().

const_iterator::const_iterator ( const const_iterator & other )

Constructs a copy of other.

const_iterator::const_iterator ( iterator other )

Constructs a copy of other.

bool const_iterator::operator!= ( const const_iterator & other ) const

Returns true if other points to a different item than this iterator; otherwise returns false.

See also operator==().

const T & const_iterator::operator* () const

Returns a reference to the current item.

See also operator->().

const_iterator const_iterator::operator+ ( int j ) const

Returns an iterator to the item at j positions forward from this iterator. (If j is negative, the iterator goes backward.)

This operation can be slow for large j values.

See also operator-().

const_iterator & const_iterator::operator++ ()

The prefix ++ operator (++it) advances the iterator to the next item in the list and returns an iterator to the new current item.

Calling this function on QLinkedList::constEnd() leads to undefined results.

See also operator--().

const_iterator const_iterator::operator++ ( int )

This is an overloaded member function, provided for convenience.

The postfix ++ operator (it++) advances the iterator to the next item in the list and returns an iterator to the previously current item.

const_iterator & const_iterator::operator+= ( int j )

Advances the iterator by j items. (If j is negative, the iterator goes backward.)

This operation can be slow for large j values.

See also operator-=() and operator+().

const_iterator const_iterator::operator- ( int j ) const

Returns an iterator to the item at j positions backward from this iterator. (If j is negative, the iterator goes forward.)

This operation can be slow for large j values.

See also operator+().

const_iterator & const_iterator::operator-- ()

The prefix -- operator (--it) makes the preceding item current and returns an iterator to the new current item.

Calling this function on QLinkedList::begin() leads to undefined results.

See also operator++().

const_iterator const_iterator::operator-- ( int )

This is an overloaded member function, provided for convenience.

The postfix -- operator (it--) makes the preceding item current and returns an iterator to the previously current item.

const_iterator & const_iterator::operator-= ( int j )

Makes the iterator go back by j items. (If j is negative, the iterator goes forward.)

This operation can be slow for large j values.

See also operator+=() and operator-().

const T * const_iterator::operator-> () const

Returns a pointer to the current item.

See also operator*().

const_iterator & const_iterator::operator= ( const const_iterator & other )

Assigns other to this iterator.

bool const_iterator::operator== ( const const_iterator & other ) const

Returns true if other points to the same item as this iterator; otherwise returns false.

See also operator!=().

Publicité

Best Of

Actualités les plus lues

Semaine
Mois
Année

Le Qt Quarterly au hasard

Logo

Des apparences personnalisées utilisant les feuilles de style

Qt Quarterly est la revue trimestrielle proposée par Nokia et à destination des développeurs Qt. Ces articles d'une grande qualité technique sont rédigés par des experts Qt. Lire l'article.

Communauté

Ressources

Liens utiles

Contact

  • Vous souhaitez rejoindre la rédaction ou proposer un tutoriel, une traduction, une question... ? Postez dans le forum Contribuez ou contactez-nous par MP ou par email (voir en bas de page).

Qt dans le magazine

Cette page est une traduction d'une page de la documentation de Qt, écrite par Nokia Corporation and/or its subsidiary(-ies). Les éventuels problèmes résultant d'une mauvaise traduction ne sont pas imputables à Nokia. Qt 4.2
Copyright © 2012 Developpez LLC. Tous droits réservés Developpez LLC. Aucune reproduction, même partielle, ne peut être faite de ce site et de l'ensemble de son contenu : textes, documents et images sans l'autorisation expresse de Developpez LLC. Sinon, vous encourez selon la loi jusqu'à 3 ans de prison et jusqu'à 300 000 E de dommages et intérêts. Cette page est déposée à la SACD.
Vous avez déniché une erreur ? Un bug ? Une redirection cassée ? Ou tout autre problème, quel qu'il soit ? Ou bien vous désirez participer à ce projet de traduction ? N'hésitez pas à nous contacter ou par MP !
 
 
 
 
Partenaires

Hébergement Web