QLinkedListIterator Class

The QLinkedListIterator class provides a Java-style const iterator for QLinkedList. More...

Header: #include <QLinkedListIterator>
qmake: QT += core

Public Functions

QLinkedListIterator(const QLinkedList<T> &list)
QLinkedListIterator<T> &operator=(const QLinkedList<T> &container)
bool findNext(const T &value)
bool findPrevious(const T &value)
bool hasNext() const
bool hasPrevious() const
const T &next()
const T &peekNext() const
const T &peekPrevious() const
const T &previous()
void toBack()
void toFront()

Detailed Description

QLinkedList has both Java-style iterators and STL-style iterators. The Java-style iterators are more high-level and easier to use than the STL-style iterators; on the other hand, they are slightly less efficient.

QLinkedListIterator<T> allows you to iterate over a QLinkedList<T>. If you want to modify the list as you iterate over it, use QMutableLinkedListIterator<T> instead.

The QLinkedListIterator constructor takes a QLinkedList as argument. After construction, the iterator is located at the very beginning of the list (before the first item). Here's how to iterate over all the elements sequentially:

QLinkedList<float> list;
...
QLinkedListIterator<float> i(list);
while (i.hasNext())
    qDebug() << i.next();

The next() function returns the next item in the list and advances the iterator. Unlike STL-style iterators, Java-style iterators point between items rather than directly at items. The first call to next() advances the iterator to the position between the first and second item, and returns the first item; the second call to next() advances the iterator to the position between the second and third item, and returns the second item; and so on.

Here's how to iterate over the elements in reverse order:

QLinkedListIterator<float> i(list);
i.toBack();
while (i.hasPrevious())
    qDebug() << i.previous();

If you want to find all occurrences of a particular value, use findNext() or findPrevious() in a loop.

Multiple iterators can be used on the same list. If the list is modified while a QLinkedListIterator is active, the QLinkedListIterator will continue iterating over the original list, ignoring the modified copy.

See also QMutableLinkedListIterator and QLinkedList::const_iterator.

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