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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>TQPtrListIterator Class Reference</h1>
<p>The TQPtrListIterator class provides an iterator for
TQPtrList collections.
<a href="#details">More...</a>
<p><tt>#include <<a href="tqptrlist-h.html">tqptrlist.h</a>></tt>
<p>Inherited by <a href="tqobjectlistiterator.html">TQObjectListIterator</a> and <a href="tqstrlistiterator.html">TQStrListIterator</a>.
<p><a href="tqptrlistiterator-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#TQPtrListIterator"><b>TQPtrListIterator</b></a> ( const TQPtrList<type> & list )</li>
<li class=fn><a href="#~TQPtrListIterator"><b>~TQPtrListIterator</b></a> ()</li>
<li class=fn>uint <a href="#count"><b>count</b></a> () const</li>
<li class=fn>bool <a href="#isEmpty"><b>isEmpty</b></a> () const</li>
<li class=fn>bool <a href="#atFirst"><b>atFirst</b></a> () const</li>
<li class=fn>bool <a href="#atLast"><b>atLast</b></a> () const</li>
<li class=fn>type * <a href="#toFirst"><b>toFirst</b></a> ()</li>
<li class=fn>type * <a href="#toLast"><b>toLast</b></a> ()</li>
<li class=fn><a href="#operator-type-*"><b>operator type *</b></a> () const</li>
<li class=fn>type * <a href="#operator*"><b>operator*</b></a> ()</li>
<li class=fn>type * <a href="#current"><b>current</b></a> () const</li>
<li class=fn>type * <a href="#operator()"><b>operator()</b></a> ()</li>
<li class=fn>type * <a href="#operator++"><b>operator++</b></a> ()</li>
<li class=fn>type * <a href="#operator+-eq"><b>operator+=</b></a> ( uint jump )</li>
<li class=fn>type * <a href="#operator--"><b>operator--</b></a> ()</li>
<li class=fn>type * <a href="#operator--eq"><b>operator-=</b></a> ( uint jump )</li>
<li class=fn>TQPtrListIterator<type> & <a href="#operator-eq"><b>operator=</b></a> ( const TQPtrListIterator<type> & it )</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The TQPtrListIterator class provides an iterator for
<a href="tqptrlist.html">TQPtrList</a> collections.
<p>
<p> Define a template instance TQPtrListIterator<X> to create a list
iterator that operates on TQPtrList<X> (list of X*).
<p> The following example is similar to the <a href="tqptrlist.html#example">example in the TQPtrList class documentation</a>, but it uses TQPtrListIterator. The class Employee is
defined there.
<p> <pre>
<a href="tqptrlist.html">TQPtrList</a><Employee> list;
list.<a href="tqptrlist.html#append">append</a>( new Employee("John", "Doe", 50000) );
list.<a href="tqptrlist.html#append">append</a>( new Employee("Jane", "Williams", 80000) );
list.<a href="tqptrlist.html#append">append</a>( new Employee("Tom", "Jones", 60000) );
TQPtrListIterator<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="tqptrlist.html">TQPtrList</a> member functions <a href="tqptrlist.html#first">first</a>(), <a href="tqptrlist.html#next">next</a>(), <a href="tqptrlist.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="tqptrlist.html#current">TQPtrList::current</a>() instead to
avoid dangling references.
<p> <p>See also <a href="tqptrlist.html">TQPtrList</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="TQPtrListIterator"></a>TQPtrListIterator::TQPtrListIterator ( const <a href="tqptrlist.html">TQPtrList</a><type> & list )
</h3>
<p> 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="~TQPtrListIterator"></a>TQPtrListIterator::~TQPtrListIterator ()
</h3>
<p> Destroys the iterator.
<h3 class=fn>bool <a name="atFirst"></a>TQPtrListIterator::atFirst () const
</h3>
<p> Returns TRUE if the current iterator item is the first list item;
otherwise returns FALSE.
<p> <p>See also <a href="#toFirst">toFirst</a>() and <a href="#atLast">atLast</a>().
<h3 class=fn>bool <a name="atLast"></a>TQPtrListIterator::atLast () const
</h3>
<p> Returns TRUE if the current iterator item is the last list item;
otherwise returns FALSE.
<p> <p>See also <a href="#toLast">toLast</a>() and <a href="#atFirst">atFirst</a>().
<h3 class=fn>uint <a name="count"></a>TQPtrListIterator::count () const
</h3>
<p> Returns the number of items in the list this iterator operates on.
<p> <p>See also <a href="#isEmpty">isEmpty</a>().
<p>Example: <a href="customlayout-example.html#x1522">customlayout/card.cpp</a>.
<h3 class=fn>type * <a name="current"></a>TQPtrListIterator::current () const
</h3>
<p> 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, 0 is returned.
<p>Examples: <a href="canvas-example.html#x2949">canvas/canvas.cpp</a>, <a href="customlayout-example.html#x1523">customlayout/card.cpp</a>, and <a href="customlayout-example.html#x1481">customlayout/flow.cpp</a>.
<h3 class=fn>bool <a name="isEmpty"></a>TQPtrListIterator::isEmpty () const
</h3>
<p> Returns TRUE if the list is empty; otherwise returns FALSE.
<p> <p>See also <a href="#count">count</a>().
<h3 class=fn><a name="operator-type-*"></a>TQPtrListIterator::operator type * () const
</h3>
<p> 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>TQPtrListIterator::operator() ()
</h3>
<p> 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 0, 0 is returned.
<h3 class=fn>type * <a name="operator*"></a>TQPtrListIterator::operator* ()
</h3>
<p> Asterisk operator. Returns a pointer to the current iterator item.
Same as <a href="#current">current</a>().
<h3 class=fn>type * <a name="operator++"></a>TQPtrListIterator::operator++ ()
</h3>
<p> 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 0, 0 is returned.
<h3 class=fn>type * <a name="operator+-eq"></a>TQPtrListIterator::operator+= ( uint jump )
</h3>
<p> 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 0 and returns 0
<h3 class=fn>type * <a name="operator--"></a>TQPtrListIterator::operator-- ()
</h3>
<p> 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 0, 0 is returned.
<h3 class=fn>type * <a name="operator--eq"></a>TQPtrListIterator::operator-= ( uint jump )
</h3>
<p> Returns the item <em>jump</em> positions before the current item or 0
if it is beyond the first item. Makes this the current item.
<h3 class=fn><a href="tqptrlistiterator.html">TQPtrListIterator</a><type> & <a name="operator-eq"></a>TQPtrListIterator::operator= ( const <a href="tqptrlistiterator.html">TQPtrListIterator</a><type> & it )
</h3>
<p> 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>TQPtrListIterator::toFirst ()
</h3>
<p> Sets the current iterator item to point to the first list item and
returns a pointer to the item. Sets the current item to 0 and
returns 0 if the list is empty.
<p> <p>See also <a href="#toLast">toLast</a>() and <a href="#atFirst">atFirst</a>().
<h3 class=fn>type * <a name="toLast"></a>TQPtrListIterator::toLast ()
</h3>
<p> Sets the current iterator item to point to the last list item and
returns a pointer to the item. Sets the current item to 0 and
returns 0 if the list is empty.
<p> <p>See also <a href="#toFirst">toFirst</a>() and <a href="#atLast">atLast</a>().
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