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<td align="right" valign="top" width="230"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></td></tr></table><h1 align="center">QList::iterator Class Reference</h1>

<p>The QList::iterator class provides an STL-style non-const iterator for <a href="qlist.html">QList</a> and <a href="qqueue.html">QQueue</a>. <a href="#details">More...</a></p>

<pre>#include <QList></pre><p>Part of the <a href="qtcore.html">QtCore</a> module.</p>

<ul>

<li><a href="qlist-iterator-members.html">List of all members, including inherited members</a></li>

</ul>

<h3>Public Functions</h3>

<ul>

<li><div class="fn"/><b><a href="qlist-iterator.html#iterator">iterator</a></b> ()</li>

<li><div class="fn"/><b><a href="qlist-iterator.html#iterator-3">iterator</a></b> ( const iterator & <i>other</i> )</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-not-eq">operator!=</a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-not-eq-2">operator!=</a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>T & <b><a href="qlist-iterator.html#operator-2a">operator*</a></b> () const</li>

<li><div class="fn"/>iterator <b><a href="qlist-iterator.html#operator-2b">operator+</a></b> ( int <i>j</i> ) const</li>

<li><div class="fn"/>iterator & <b><a href="qlist-iterator.html#operator-2b-2b">operator++</a></b> ()</li>

<li><div class="fn"/>iterator <b><a href="qlist-iterator.html#operator-2b-2b-2">operator++</a></b> ( int )</li>

<li><div class="fn"/>iterator & <b><a href="qlist-iterator.html#operator-2b-eq">operator+=</a></b> ( int <i>j</i> )</li>

<li><div class="fn"/>iterator <b><a href="qlist-iterator.html#operator-">operator-</a></b> ( int <i>j</i> ) const</li>

<li><div class="fn"/>int <b><a href="qlist-iterator.html#operator--2">operator-</a></b> ( iterator <i>other</i> ) const</li>

<li><div class="fn"/>iterator & <b><a href="qlist-iterator.html#operator--">operator--</a></b> ()</li>

<li><div class="fn"/>iterator <b><a href="qlist-iterator.html#operator---2">operator--</a></b> ( int )</li>

<li><div class="fn"/>iterator & <b><a href="qlist-iterator.html#operator--eq">operator-=</a></b> ( int <i>j</i> )</li>

<li><div class="fn"/>T * <b><a href="qlist-iterator.html#operator--gt">operator-></a></b> () const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-lt">operator<</a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-lt-2">operator<</a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-lt-eq">operator<=</a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-lt-eq-2">operator<=</a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-eq-eq">operator==</a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-eq-eq-2">operator==</a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-gt">operator></a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-gt-2">operator></a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-gt-eq">operator>=</a></b> ( const iterator & <i>other</i> ) const</li>

<li><div class="fn"/>bool <b><a href="qlist-iterator.html#operator-gt-eq-2">operator>=</a></b> ( const const_iterator & <i>other</i> ) const</li>

<li><div class="fn"/>T & <b><a href="qlist-iterator.html#operator-5b-5d">operator[]</a></b> ( int <i>j</i> ) const</li>

</ul>

<hr />

<h2>Detailed Description</h2>

<p>The QList::iterator class provides an STL-style non-const iterator for <a href="qlist.html">QList</a> and <a href="qqueue.html">QQueue</a>.</p>

<p><a href="qlist.html">QList</a> features both <a href="containers.html#stl-style-iterators">STL-style iterators</a> and <a href="containers.html#java-style-iterators">Java-style iterators</a>. 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.</p>

<p><a href="qlist.html">QList</a><T>::iterator allows you to iterate over a <a href="qlist.html">QList</a><T> (or <a href="qqueue.html">QQueue</a><T>) and to modify the list item associated with the iterator. If you want to iterate over a const <a href="qlist.html">QList</a>, use <a href="qlist-const-iterator.html">QList::const_iterator</a> instead. It is generally good practice to use <a href="qlist-const-iterator.html">QList::const_iterator</a> on a non-const <a href="qlist.html">QList</a> as well, unless you need to change the <a href="qlist.html">QList</a> through the iterator. Const iterators are slightly faster, and can improve code readability.</p>

<p>The default QList::iterator constructor creates an uninitialized iterator. You must initialize it using a <a href="qlist.html">QList</a> function like <a href="qlist.html#begin">QList::begin</a>(), <a href="qlist.html#end">QList::end</a>(), or <a href="qlist.html#insert">QList::insert</a>() before you can start iterating. Here's a typical loop that prints all the items stored in a list:</p>

<pre>  QList<QString> list;

list.append("January");

list.append("February");

...

list.append("December");

QList<QString>::iterator i;

for (i = list.begin(); i != list.end(); ++i)

cout << *i << endl;</pre>

<p>Let's see a few examples of things we can do with a QList::iterator that we cannot do with a <a href="qlist-const-iterator.html">QList::const_iterator</a>. Here's an example that increments every value stored in a <a href="qlist.html">QList</a><int> by 2:</p>

<pre>  QList<int>::iterator i;

for (i = list.begin(); i != list.end(); ++i)

*i += 2;</pre>

<p>Most <a href="qlist.html">QList</a> functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with <a href="qlist.html">QList</a>. One place where STL-style iterators do make sense is as arguments to <a href="qtalgorithms.html">generic algorithms</a>.</p>

<p>For example, here's how to delete all the widgets stored in a <a href="qlist.html">QList</a><<a href="qwidget.html">QWidget</a> *>:</p>

<pre>  QList<QWidget *> list;

...

qDeleteAll(list.begin(), list.end());</pre>

<p>Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the <a href="qlist.html">QList</a> will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use <a href="qlinkedlist.html">QLinkedList</a> rather than <a href="qlist.html">QList</a>.</p>

<p>See also <a href="qlist-const-iterator.html">QList::const_iterator</a> and <a href="qmutablelistiterator.html">QMutableListIterator</a>.</p>

<hr />

<h2>Member Function Documentation</h2>

<h3 class="fn"><a name="iterator"></a>iterator::iterator ()</h3>

<p>Constructs an uninitialized iterator.</p>

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

<p>See also <a href="qlist.html#begin">QList::begin</a>() and <a href="qlist.html#end">QList::end</a>().</p>

<h3 class="fn"><a name="iterator-3"></a>iterator::iterator ( const iterator & <i>other</i> )</h3>

<p>Constructs a copy of <i>other</i>.</p>

<h3 class="fn"><a name="operator-not-eq"></a>bool iterator::operator!= ( const iterator & <i>other</i> ) const</h3>

<p>Returns true if <i>other</i> points to a different item than this iterator; otherwise returns false.</p>

<p>See also <a href="qlist-iterator.html#operator-eq-eq">operator==</a>().</p>

<h3 class="fn"><a name="operator-not-eq-2"></a>bool iterator::operator!= ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

<p>Returns true if <i>other</i> points to a different item than this iterator; otherwise returns false.</p>

<p>See also <a href="qlist-iterator.html#operator-eq-eq">operator==</a>().</p>

<h3 class="fn"><a name="operator-2a"></a>T & iterator::operator* () const</h3>

<p>Returns a modifiable reference to the current item.</p>

100

<p>You can change the value of an item by using operator*() on the left side of an assignment, for example:</p>

101

<pre>  if (*it == "Hello")

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*it = "Bonjour";</pre>

103

<p>See also <a href="qlist-iterator.html#operator--gt">operator-></a>().</p>

104

<h3 class="fn"><a name="operator-2b"></a>iterator iterator::operator+ ( int <i>j</i> ) const</h3>

105

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

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<p>See also <a href="qlist-iterator.html#operator-">operator-</a>() and <a href="qlist-iterator.html#operator-2b-eq">operator+=</a>().</p>

107

<h3 class="fn"><a name="operator-2b-2b"></a>iterator & iterator::operator++ ()</h3>

108

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

109

<p>Calling this function on <a href="qlist.html#end">QList::end</a>() leads to undefined results.</p>

110

<p>See also <a href="qlist-iterator.html#operator--">operator--</a>().</p>

111

<h3 class="fn"><a name="operator-2b-2b-2"></a>iterator iterator::operator++ ( int )</h3>

112

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

113

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

114

<h3 class="fn"><a name="operator-2b-eq"></a>iterator & iterator::operator+= ( int <i>j</i> )</h3>

115

<p>Advances the iterator by <i>j</i> items. (If <i>j</i> is negative, the iterator goes backward.)</p>

116

<p>See also <a href="qlist-iterator.html#operator--eq">operator-=</a>() and <a href="qlist-iterator.html#operator-2b">operator+</a>().</p>

117

<h3 class="fn"><a name="operator-"></a>iterator iterator::operator- ( int <i>j</i> ) const</h3>

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

119

<p>See also <a href="qlist-iterator.html#operator-2b">operator+</a>() and <a href="qlist-iterator.html#operator--eq">operator-=</a>().</p>

120

<h3 class="fn"><a name="operator--2"></a>int iterator::operator- ( iterator <i>other</i> ) const</h3>

121

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

122

<p>Returns the number of items between the item pointed to by <i>other</i> and the item pointed to by this iterator.</p>

123

<h3 class="fn"><a name="operator--"></a>iterator & iterator::operator-- ()</h3>

124

<p>The prefix -- operator (<tt>--it</tt>) makes the preceding item current and returns an iterator to the new current item.</p>

125

<p>Calling this function on <a href="qlist.html#begin">QList::begin</a>() leads to undefined results.</p>

126

<p>See also <a href="qlist-iterator.html#operator-2b-2b">operator++</a>().</p>

127

<h3 class="fn"><a name="operator---2"></a>iterator iterator::operator-- ( int )</h3>

128

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

129

<p>The postfix -- operator (<tt>it--</tt>) makes the preceding item current and returns an iterator to the previously current item.</p>

130

<h3 class="fn"><a name="operator--eq"></a>iterator & iterator::operator-= ( int <i>j</i> )</h3>

131

<p>Makes the iterator go back by <i>j</i> items. (If <i>j</i> is negative, the iterator goes forward.)</p>

132

<p>See also <a href="qlist-iterator.html#operator-2b-eq">operator+=</a>() and <a href="qlist-iterator.html#operator-">operator-</a>().</p>

133

<h3 class="fn"><a name="operator--gt"></a>T * iterator::operator-> () const</h3>

134

<p>Returns a pointer to the current item.</p>

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<p>See also <a href="qlist-iterator.html#operator-2a">operator*</a>().</p>

136

<h3 class="fn"><a name="operator-lt"></a>bool iterator::operator< ( const iterator & <i>other</i> ) const</h3>

137

<p>Returns true if the item pointed to by this iterator is less than the item pointed to by the <i>other</i> iterator.</p>

138

<h3 class="fn"><a name="operator-lt-2"></a>bool iterator::operator< ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

139

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

140

<p>Returns true if the item pointed to by this iterator is less than the item pointed to by the <i>other</i> iterator.</p>

141

<h3 class="fn"><a name="operator-lt-eq"></a>bool iterator::operator<= ( const iterator & <i>other</i> ) const</h3>

142

<p>Returns true if the item pointed to by this iterator is less than or equal to the item pointed to by the <i>other</i> iterator.</p>

143

<h3 class="fn"><a name="operator-lt-eq-2"></a>bool iterator::operator<= ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

144

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

145

<p>Returns true if the item pointed to by this iterator is less than or equal to the item pointed to by the <i>other</i> iterator.</p>

146

<h3 class="fn"><a name="operator-eq-eq"></a>bool iterator::operator== ( const iterator & <i>other</i> ) const</h3>

147

<p>Returns true if <i>other</i> points to the same item as this iterator; otherwise returns false.</p>

148

<p>See also <a href="qlist-iterator.html#operator-not-eq">operator!=</a>().</p>

149

<h3 class="fn"><a name="operator-eq-eq-2"></a>bool iterator::operator== ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

150

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

151

<p>Returns true if <i>other</i> points to the same item as this iterator; otherwise returns false.</p>

152

<p>See also <a href="qlist-iterator.html#operator-not-eq">operator!=</a>().</p>

153

<h3 class="fn"><a name="operator-gt"></a>bool iterator::operator> ( const iterator & <i>other</i> ) const</h3>

154

<p>Returns true if the item pointed to by this iterator is greater than the item pointed to by the <i>other</i> iterator.</p>

155

<h3 class="fn"><a name="operator-gt-2"></a>bool iterator::operator> ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

156

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

157

<p>Returns true if the item pointed to by this iterator is greater than the item pointed to by the <i>other</i> iterator.</p>

158

<h3 class="fn"><a name="operator-gt-eq"></a>bool iterator::operator>= ( const iterator & <i>other</i> ) const</h3>

159

<p>Returns true if the item pointed to by this iterator is greater than or equal to the item pointed to by the <i>other</i> iterator.</p>

160

<h3 class="fn"><a name="operator-gt-eq-2"></a>bool iterator::operator>= ( const <a href="qlist-const-iterator.html">const_iterator</a> & <i>other</i> ) const</h3>

161

<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>

162

<p>Returns true if the item pointed to by this iterator is greater than or equal to the item pointed to by the <i>other</i> iterator.</p>

163

<h3 class="fn"><a name="operator-5b-5d"></a>T & iterator::operator[] ( int <i>j</i> ) const</h3>

164

<p>Returns a modifiable reference to the item at position *this + <i>j</i>.</p>

165

<p>This function is provided to make <a href="qlist.html">QList</a> iterators behave like C++ pointers.</p>

166

<p>See also <a href="qlist-iterator.html#operator-2b">operator+</a>().</p>

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<td width="40%" align="center"><a href="trademarks.html">Trademarks</a></td>

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