1QPtrListIterator(3qt) QPtrListIterator(3qt)
2
6 QPtrListIterator - Iterator for QPtrList collections
7
9 #include <qptrlist.h>
10 Inherited by QObjectListIterator and QStrListIterator.
12 Public Members
14 QPtrListIterator ( const QPtrList<type> & list )
15 ~QPtrListIterator ()
16 uint count () const
17 bool isEmpty () const
18 bool atFirst () const
19 bool atLast () const
20 type * toFirst ()
21 type * toLast ()
22 operator type * () const
23 type * operator* ()
24 type * current () const
25 type * operator() ()
26 type * operator++ ()
27 type * operator+= ( uint jump )
28 type * operator-- ()
29 type * operator-= ( uint jump )
30 QPtrListIterator<type> & operator= ( const QPtrListIterator<type> & it
31 )
32
34 The QPtrListIterator class provides an iterator for QPtrList
35 collections.
36 Define a template instance QPtrListIterator<X> to create a list
38 iterator that operates on QPtrList<X> (list of X*).
39 The following example is similar to the example in the QPtrList class
41 documentation, but it uses QPtrListIterator. The class Employee is
42 defined there.
43 QPtrList<Employee> list;
45 list.append( new Employee("John", "Doe", 50000) );
46 list.append( new Employee("Jane", "Williams", 80000) );
47 list.append( new Employee("Tom", "Jones", 60000) );
48 QPtrListIterator<Employee> it( list );
49 Employee *employee;
50 while ( (employee = it.current()) != 0 ) {
51 ++it;
52 cout << employee->surname().latin1() << ", " <<
53 employee->forename().latin1() << " earns " <<
54 employee->salary() << endl;
55 }
56 The output is
58 Doe, John earns 50000
60 Williams, Jane earns 80000
61 Jones, Tom earns 60000
62 Using a list iterator is a more robust way of traversing the list than
64 using the QPtrList member functions first(), next(), current(), etc.,
65 as many iterators can traverse the same list independently.
66 An iterator has its own current list item and can get the next and
68 previous list items. It doesn't modify the list in any way.
69 When an item is removed from the list, all iterators that point to that
71 item are updated to point to QPtrList::current() instead to avoid
72 dangling references.
73 See also QPtrList, Collection Classes, and Non-GUI Classes.
75
78 Constructs an iterator for list. The current iterator item is set to
79 point on the first item in the list.
80
82 Destroys the iterator.
83
85 Returns TRUE if the current iterator item is the first list item;
86 otherwise returns FALSE.
87 See also toFirst() and atLast().
89
91 Returns TRUE if the current iterator item is the last list item;
92 otherwise returns FALSE.
93 See also toLast() and atFirst().
95
97 Returns the number of items in the list this iterator operates on.
98 See also isEmpty().
100 Example: customlayout/card.cpp.
102
104 Returns a pointer to the current iterator item. If the iterator is
105 positioned before the first item in the list or after the last item in
106 the list, 0 is returned.
107 Examples:
109
111 Returns TRUE if the list is empty; otherwise returns FALSE.
112 See also count().
114
116 Cast operator. Returns a pointer to the current iterator item. Same as
117 current().
118
120 Makes the succeeding item current and returns the original current
121 item.
122 If the current iterator item was the last item in the list or if it was
124 0, 0 is returned.
125
127 Asterisk operator. Returns a pointer to the current iterator item. Same
128 as current().
129
131 Prefix ++ makes the succeeding item current and returns the new current
132 item.
133 If the current iterator item was the last item in the list or if it was
135 0, 0 is returned.
136
138 Sets the current item to the item jump positions after the current item
139 and returns a pointer to that item.
140 If that item is beyond the last item or if the list is empty, it sets
142 the current item to 0 and returns 0
143
145 Prefix - makes the preceding item current and returns the new current
146 item.
147 If the current iterator item was the first item in the list or if it
149 was 0, 0 is returned.
150
152 Returns the item jump positions before the current item or 0 if it is
153 beyond the first item. Makes this the current item.
154
156 QPtrListIterator<type> & it )
157 Assignment. Makes a copy of the iterator it and returns a reference to
158 this iterator.
159
161 Sets the current iterator item to point to the first list item and
162 returns a pointer to the item. Sets the current item to 0 and returns 0
163 if the list is empty.
164 See also toLast() and atFirst().
166
168 Sets the current iterator item to point to the last list item and
169 returns a pointer to the item. Sets the current item to 0 and returns 0
170 if the list is empty.
171 See also toFirst() and atLast().
173
176 http://doc.trolltech.com/qptrlistiterator.html
177 http://www.trolltech.com/faq/tech.html
178
180 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
181 license file included in the distribution for a complete license
182 statement.
183
185 Generated automatically from the source code.
186
188 If you find a bug in Qt, please report it as described in
189 http://doc.trolltech.com/bughowto.html. Good bug reports help us to
190 help you. Thank you.
191 The definitive Qt documentation is provided in HTML format; it is
193 located at $QTDIR/doc/html and can be read using Qt Assistant or with a
194 web browser. This man page is provided as a convenience for those users
195 who prefer man pages, although this format is not officially supported
196 by Trolltech.
197 If you find errors in this manual page, please report them to qt-
199 bugs@trolltech.com. Please include the name of the manual page
200 (qptrlistiterator.3qt) and the Qt version (3.3.8).
201Trolltech AS 2 February 2007 QPtrListIterator(3qt)