The QLinkedList::const_iterator 類提供 STL 樣式 const 迭代器為 QLinkedList . 更多...
| 頭： | #include <const_iterator> |
| qmake: | QT += core |
| const_iterator () | |
| const_iterator (iterator other ) | |
| const_iterator (const const_iterator & other ) | |
| const_iterator (const_iterator && other ) | |
| bool | operator!= (const const_iterator & other ) const |
| const T & | operator* () const |
| const_iterator | operator+ (int j ) const |
| const_iterator & | operator++ () |
| const_iterator | operator++ ( int ) |
| const_iterator & | operator+= (int j ) |
| const_iterator | operator- (int j ) const |
| const_iterator & | operator-- () |
| const_iterator | operator-- ( int ) |
| const_iterator & | operator-= (int j ) |
| const T * | operator-> () const |
| const_iterator & | operator= (const const_iterator & other ) |
| const_iterator & | operator= (const_iterator && other ) |
| bool | operator== (const const_iterator & other ) const |
| QLinkedList::Node * | i |
The QLinkedList::const_iterator 類提供 STL 樣式 const 迭代器為 QLinkedList .
QLinkedList features both STL 樣式迭代器 and Java 風格迭代器 . 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::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.
默認 QLinkedList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a function like QLinkedList::constBegin (), QLinkedList::constEnd ()，或 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 一般算法 . 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.
警告： Iterators on implicitly shared containers do not work exactly like STL-iterators. You should avoid copying a container while iterators are active on that container. For more information, read 隱式共享迭代器問題 .
另請參閱 QLinkedList::iterator and QLinkedListIterator .
Constructs an uninitialized iterator.
Functions like operator*() and operator++() should not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it.
另請參閱 QLinkedList::constBegin () 和 QLinkedList::constEnd ().
構造副本為 other .
構造副本為 other .
Default constructs an instance of const_iterator.
返迴
true
if
other
指嚮與此迭代器不同的項；否則返迴
false
.
另請參閱 operator== ().
Returns a reference to the current item.
另請參閱 operator-> ().
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 值。
另請參閱 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 <T>::constEnd() leads to undefined results.
另請參閱 operator-- ().
這是重載函數。
The postfix ++ operator (
it++
) advances the iterator to the next item in the list and returns an iterator to the previously current item.
推進迭代器 j items. (If j is negative, the iterator goes backward.)
This operation can be slow for large j 值。
另請參閱 operator-= () 和 operator+ ().
This function 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 值。
另請參閱 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.
另請參閱 operator++ ().
這是重載函數。
The postfix -- operator (
it--
) makes the preceding item current and returns an iterator to the previously current item.
Makes the iterator go back by j items. (If j is negative, the iterator goes forward.)
This operation can be slow for large j 值。
另請參閱 operator+= () 和 operator- ().
Returns a pointer to the current item.
另請參閱 operator* ().
賦值 other to this iterator.
移動賦值運算符。
返迴
true
if
other
points to the same item as this iterator; otherwise returns
false
.
另請參閱 operator!= ().
