<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- /tmp/qt-3.0-reggie-28534/qt-x11-free-3.0.2/doc/qptrlist.doc:725 -->
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>QPtrListIterator Class</title>
<style type="text/css"><!--
h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }
a:link { color: #004faf; text-decoration: none }
a:visited { color: #672967; text-decoration: none }
body { background: #ffffff; color: black; }
--></style>
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr bgcolor="#E5E5E5">
<td valign=center>
<a href="index.html">
<font color="#004faf">Home</font></a>
| <a href="classes.html">
<font color="#004faf">All Classes</font></a>
| <a href="mainclasses.html">
<font color="#004faf">Main Classes</font></a>
| <a href="annotated.html">
<font color="#004faf">Annotated</font></a>
| <a href="groups.html">
<font color="#004faf">Grouped Classes</font></a>
| <a href="functions.html">
<font color="#004faf">Functions</font></a>
</td>
<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QPtrListIterator Class Reference</h1>
<p>The QPtrListIterator class provides an iterator for QPtrList
collections.
<a href="#details">More...</a>
<p><tt>#include <<a href="qptrlist-h.html">qptrlist.h</a>></tt>
<p>Inherited by <a href="qstrlistiterator.html">QStrListIterator</a>.
<p><a href="qptrlistiterator-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li><div class=fn><a href="#QPtrListIterator"><b>QPtrListIterator</b></a> ( const QPtrList<type> & list )</div></li>
<li><div class=fn><a href="#~QPtrListIterator"><b>~QPtrListIterator</b></a> ()</div></li>
<li><div class=fn>uint <a href="#count"><b>count</b></a> () const</div></li>
<li><div class=fn>bool <a href="#isEmpty"><b>isEmpty</b></a> () const</div></li>
<li><div class=fn>bool <a href="#atFirst"><b>atFirst</b></a> () const</div></li>
<li><div class=fn>bool <a href="#atLast"><b>atLast</b></a> () const</div></li>
<li><div class=fn>type * <a href="#toFirst"><b>toFirst</b></a> ()</div></li>
<li><div class=fn>type * <a href="#toLast"><b>toLast</b></a> ()</div></li>
<li><div class=fn><a href="#operator-type-*"><b>operator type *</b></a> () const</div></li>
<li><div class=fn>type * <a href="#operator*"><b>operator*</b></a> ()</div></li>
<li><div class=fn>type * <a href="#current"><b>current</b></a> () const</div></li>
<li><div class=fn>type * <a href="#operator()"><b>operator()</b></a> ()</div></li>
<li><div class=fn>type * <a href="#operator++"><b>operator++</b></a> ()</div></li>
<li><div class=fn>type * <a href="#operator+-eq"><b>operator+=</b></a> ( uint jump )</div></li>
<li><div class=fn>type * <a href="#operator--"><b>operator--</b></a> ()</div></li>
<li><div class=fn>type * <a href="#operator--eq"><b>operator-=</b></a> ( uint jump )</div></li>
<li><div class=fn>QPtrListIterator<type> & <a href="#operator-eq"><b>operator=</b></a> ( const QPtrListIterator<type> & it )</div></li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The QPtrListIterator class provides an iterator for <a href="qptrlist.html">QPtrList</a>
collections.
<p>
<p> Define a template instance QPtrListIterator<X> to create a list iterator
that operates on QPtrList<X> (list of X*).
<p> The following example is similar to the <a href="qptrlist.html#example">example in the QPtrList class documentation</a>, but it uses
QPtrListIterator. The class Employee is defined there.
<p> <pre>
<a href="qptrlist.html">QPtrList</a><Employee> list;
list.<a href="qptrlist.html#append">append</a>( new Employee("John", "Doe", 50000) );
list.<a href="qptrlist.html#append">append</a>( new Employee("Jane", "Williams", 80000) );
list.<a href="qptrlist.html#append">append</a>( new Employee("Tom", "Jones", 60000) );
QPtrListIterator<Employee> it( list );
Employee *employee;
while ( (employee = it.<a href="#current">current</a>()) != 0 ) {
++it;
cout << employee->surname().latin1() << ", " <<
employee->forename().latin1() << " earns " <<
employee->salary() << endl;
}
</pre>
<p> The output is
<pre>
Doe, John earns 50000
Williams, Jane earns 80000
Jones, Tom earns 60000
</pre>
<p> Using a list iterator is a more robust way of traversing the
list than using the <a href="qptrlist.html">QPtrList</a> member functions
<a href="qptrlist.html#first">first</a>(),
<a href="qptrlist.html#next">next</a>(),
<a href="qptrlist.html#current">current</a>(), etc., as many
iterators can traverse the same list independently.
<p> An iterator has its own current list item and can get the next
and previous list items. It doesn't modify the list in any way.
<p> When an item is removed from the list, all iterators that point
to that item are updated to point to <a href="qptrlist.html#current">QPtrList::current</a>()
instead to avoid dangling references.
<p> <p>See also <a href="qptrlist.html">QPtrList</a>, <a href="collection.html">Collection Classes</a> and <a href="tools.html">Non-GUI Classes</a>.
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QPtrListIterator"></a>QPtrListIterator::QPtrListIterator ( const <a href="qptrlist.html">QPtrList</a><type> & list )
</h3>
Constructs an iterator for <em>list</em>. The current iterator item is
set to point on the first item in the <em>list</em>.
<h3 class=fn><a name="~QPtrListIterator"></a>QPtrListIterator::~QPtrListIterator ()
</h3>
Destroys the iterator.
<h3 class=fn>bool <a name="atFirst"></a>QPtrListIterator::atFirst () const
</h3>
Returns TRUE if the current iterator item is the first list item; otherwise
returns FALSE.
<p>See also <a href="#toFirst">toFirst</a>() and <a href="#atLast">atLast</a>().
<h3 class=fn>bool <a name="atLast"></a>QPtrListIterator::atLast () const
</h3>
Returns TRUE if the current iterator item is the last list item; otherwise
returns FALSE.
<p>See also <a href="#toLast">toLast</a>() and <a href="#atFirst">atFirst</a>().
<h3 class=fn>uint <a name="count"></a>QPtrListIterator::count () const
</h3>
Returns the number of items in the list this iterator operates on.
<p>See also <a href="#isEmpty">isEmpty</a>().
<p>Example: <a href="customlayout-example.html#x1832">customlayout/card.cpp</a>.
<h3 class=fn>type * <a name="current"></a>QPtrListIterator::current () const
</h3>
Returns a pointer to the current iterator item.If the iterator is
positioned before the first item in the list or after the last
item in the list, a null is returned.
<p>Examples: <a href="canvas-example.html#x2549">canvas/canvas.cpp</a>, <a href="customlayout-example.html#x1833">customlayout/card.cpp</a> and <a href="customlayout-example.html#x1791">customlayout/flow.cpp</a>.
<h3 class=fn>bool <a name="isEmpty"></a>QPtrListIterator::isEmpty () const
</h3>
Returns TRUE if the list is empty; otherwise returns FALSE.
<p>See also <a href="#count">count</a>().
<h3 class=fn><a name="operator-type-*"></a>QPtrListIterator::operator type * () const
</h3>
Cast operator. Returns a pointer to the current iterator item.
Same as <a href="#current">current</a>().
<h3 class=fn>type * <a name="operator()"></a>QPtrListIterator::operator() ()
</h3>
Makes the succeeding item current and returns the original current item.
<p> If the current iterator item was the last item in the list or if it was
null, null is returned.
<h3 class=fn>type * <a name="operator*"></a>QPtrListIterator::operator* ()
</h3>
Asterix operator. Returns a pointer to the current iterator item.
Same as <a href="#current">current</a>().
<h3 class=fn>type * <a name="operator++"></a>QPtrListIterator::operator++ ()
</h3>
Prefix ++ makes the succeeding item current and returns the new current
item.
<p> If the current iterator item was the last item in the list or if it was
null, null is returned.
<h3 class=fn>type * <a name="operator+-eq"></a>QPtrListIterator::operator+= ( uint jump )
</h3>
Sets the current item to the item <em>jump</em> positions after the current item
and returns a pointer to that item.
<p> If that item is beyond the last item or if the list is empty,
it sets the current item to null and returns null
<h3 class=fn>type * <a name="operator--"></a>QPtrListIterator::operator-- ()
</h3>
Prefix - makes the preceding item current and returns the new current
item.
<p> If the current iterator item was the first item in the list or if it was
null, null is returned.
<h3 class=fn>type * <a name="operator--eq"></a>QPtrListIterator::operator-= ( uint jump )
</h3>
Returns the item <em>jump</em> positions before the current item or null if
it is beyond the first item. Makes this the current item.
<h3 class=fn><a href="qptrlistiterator.html">QPtrListIterator</a><type> & <a name="operator-eq"></a>QPtrListIterator::operator= ( const <a href="qptrlistiterator.html">QPtrListIterator</a><type> & it )
</h3>
Assignment. Makes a copy of the iterator <em>it</em> and returns a reference
to this iterator.
<h3 class=fn>type * <a name="toFirst"></a>QPtrListIterator::toFirst ()
</h3>
Sets the current iterator item to point to the first list item and returns
a pointer to the item. Sets the current item to null and returns null
if the list is empty.
<p>See also <a href="#toLast">toLast</a>() and <a href="#atFirst">atFirst</a>().
<h3 class=fn>type * <a name="toLast"></a>QPtrListIterator::toLast ()
</h3>
Sets the current iterator item to point to the last list item and returns
a pointer to the item. Sets the current item to null and returns null
if the list is empty.
<p>See also <a href="#toFirst">toFirst</a>() and <a href="#atLast">atLast</a>().
<!-- eof -->
<hr><p>
This file is part of the <a href="index.html">Qt toolkit</a>.
Copyright © 1995-2001
<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
<table width=100% cellspacing=0 border=0><tr>
<td>Copyright © 2001
<a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a>
<td align=right><div align=right>Qt version 3.0.2</div>
</table></div></address></body>
</html>
distrib
>
Mandriva
>
8.2
>
i586
>
media
>
contrib
>
by-pkgid
>
112b0974ad288f6cd55bf971ee6026a9
>
files
>
1674
