Struct qt_core::q_list_of_int::ConstIterator
source · #[repr(C)]pub struct ConstIterator { /* private fields */ }
Expand description
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
C++ class: QList<int>::const_iterator
.
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
QList provides both STL-style iterators and Java-style iterators. 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.
QList<T>::const_iterator allows you to iterate over a QList<T> (or a QQueue<T>). If you want to modify the QList as you iterate over it, use QList::iterator instead. It is generally good practice to use QList::const_iterator on a non-const QList as well, unless you need to change the QList through the iterator. Const iterators are slightly faster, and can improve code readability.
The default QList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QList function like QList::constBegin(), QList::constEnd(), or QList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list:
QList<QString> list; list.append(“January”); list.append(“February”); ... list.append(“December”);
QList<QString>::const_iterator i; for (i = list.constBegin(); i != list.constEnd(); ++i) cout << *i << endl;
Most QList functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QList. One place where STL-style iterators do make sense is as arguments to generic algorithms.
For example, here's how to delete all the widgets stored in a QList<QWidget *>:
QList<QWidget *> list; ... qDeleteAll(list.constBegin(), list.constEnd());
Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the QList will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use QLinkedList rather than QList.
Warning: 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 Implicit sharing iterator problem.
Implementations§
source§impl ConstIterator
impl ConstIterator
sourcepub unsafe fn add_assign(&self, j: c_longlong) -> Ref<ConstIterator>
pub unsafe fn add_assign(&self, j: c_longlong) -> Ref<ConstIterator>
Advances the iterator by j items.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator+=(long long j)
.
Warning: no exact match found in C++ documentation. Below is the C++ documentation for const_iterator &const_iterator::operator+=(int j)
:
Advances the iterator by j items.
See also operator-=() and operator+().
sourcepub unsafe fn copy_from(
&self,
other: impl CastInto<Ref<ConstIterator>>
) -> Ref<ConstIterator>
pub unsafe fn copy_from( &self, other: impl CastInto<Ref<ConstIterator>> ) -> Ref<ConstIterator>
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator=(const QList<int>::const_iterator& other)
.
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
QList provides both STL-style iterators and Java-style iterators. 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.
QList<T>::const_iterator allows you to iterate over a QList<T> (or a QQueue<T>). If you want to modify the QList as you iterate over it, use QList::iterator instead. It is generally good practice to use QList::const_iterator on a non-const QList as well, unless you need to change the QList through the iterator. Const iterators are slightly faster, and can improve code readability.
The default QList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QList function like QList::constBegin(), QList::constEnd(), or QList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list:
QList<QString> list; list.append(“January”); list.append(“February”); ... list.append(“December”);
QList<QString>::const_iterator i; for (i = list.constBegin(); i != list.constEnd(); ++i) cout << *i << endl;
Most QList functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QList. One place where STL-style iterators do make sense is as arguments to generic algorithms.
For example, here's how to delete all the widgets stored in a QList<QWidget *>:
QList<QWidget *> list; ... qDeleteAll(list.constBegin(), list.constEnd());
Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the QList will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use QLinkedList rather than QList.
Warning: 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 Implicit sharing iterator problem.
sourcepub unsafe fn dec(&self) -> Ref<ConstIterator>
pub unsafe fn dec(&self) -> Ref<ConstIterator>
The prefix -- operator (--it
) makes the preceding item current and returns an iterator to the new current item.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator--()
.
The prefix – operator (–it
) makes the preceding item current and returns an iterator to the new current item.
Calling this function on QAssociativeIterable::begin() leads to undefined results.
See also operator++().
sourcepub unsafe fn dec_postfix(&self, arg1: c_int) -> CppBox<ConstIterator>
pub unsafe fn dec_postfix(&self, arg1: c_int) -> CppBox<ConstIterator>
This is an overloaded function.
Calls C++ function: QList<int>::const_iterator QList<int>::const_iterator::operator--(int arg1)
.
This is an overloaded function.
The postfix -- operator (it--
) makes the preceding item current and returns an iterator to the previously current item.
sourcepub unsafe fn inc(&self) -> Ref<ConstIterator>
pub unsafe fn inc(&self) -> Ref<ConstIterator>
The prefix ++ operator (++it
) advances the iterator to the next item in the container and returns an iterator to the new current item.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator++()
.
The prefix ++ operator (++it
) advances the iterator to the next item in the container and returns an iterator to the new current item.
Calling this function on QAssociativeIterable::end() leads to undefined results.
See also operator--().
sourcepub unsafe fn inc_postfix(&self, arg1: c_int) -> CppBox<ConstIterator>
pub unsafe fn inc_postfix(&self, arg1: c_int) -> CppBox<ConstIterator>
This is an overloaded function.
Calls C++ function: QList<int>::const_iterator QList<int>::const_iterator::operator++(int arg1)
.
This is an overloaded function.
The postfix ++ operator (it++
) advances the iterator to the next item in the container and returns an iterator to the previously current item.
sourcepub unsafe fn index(&self, j: c_longlong) -> *const c_int
pub unsafe fn index(&self, j: c_longlong) -> *const c_int
Returns the item at offset j from the item pointed to by this iterator (the item at position *this + j
).
Calls C++ function: const int& QList<int>::const_iterator::operator[](long long j) const
.
Warning: no exact match found in C++ documentation. Below is the C++ documentation for QJsonValue const_iterator::operator[](int j) const
:
Returns the item at offset j from the item pointed to by this iterator (the item at position *this + j
).
This function is provided to make QJsonArray iterators behave like C++ pointers.
See also operator+().
sourcepub unsafe fn indirection(&self) -> *const c_int
pub unsafe fn indirection(&self) -> *const c_int
sourcepub unsafe fn new_0a() -> CppBox<ConstIterator>
pub unsafe fn new_0a() -> CppBox<ConstIterator>
Constructs an uninitialized iterator.
Calls C++ function: [constructor] void QList<int>::const_iterator::const_iterator()
.
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.
See also QList::constBegin() and QList::constEnd().
sourcepub unsafe fn new_1a(o: impl CastInto<Ref<Iterator>>) -> CppBox<ConstIterator>
pub unsafe fn new_1a(o: impl CastInto<Ref<Iterator>>) -> CppBox<ConstIterator>
Calls C++ function: [constructor] void QList<int>::const_iterator::const_iterator(const QList<int>::iterator& o)
.
sourcepub unsafe fn new_copy(
o: impl CastInto<Ref<ConstIterator>>
) -> CppBox<ConstIterator>
pub unsafe fn new_copy( o: impl CastInto<Ref<ConstIterator>> ) -> CppBox<ConstIterator>
Calls C++ function: [constructor] void QList<int>::const_iterator::const_iterator(const QList<int>::const_iterator& o)
.
sourcepub unsafe fn struct_deref(&self) -> *const c_int
pub unsafe fn struct_deref(&self) -> *const c_int
Returns a pointer to the current result.
Calls C++ function: const int* QList<int>::const_iterator::operator->() const
.
Returns a pointer to the current result.
sourcepub unsafe fn sub_assign(&self, j: c_longlong) -> Ref<ConstIterator>
pub unsafe fn sub_assign(&self, j: c_longlong) -> Ref<ConstIterator>
Makes the iterator go back by j items.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator-=(long long j)
.
Warning: no exact match found in C++ documentation. Below is the C++ documentation for const_iterator &const_iterator::operator-=(int j)
:
Makes the iterator go back by j items.
See also operator+=() and operator-().
Trait Implementations§
source§impl Add<i64> for &ConstIterator
impl Add<i64> for &ConstIterator
source§fn add(self, j: c_longlong) -> CppBox<ConstIterator>
fn add(self, j: c_longlong) -> CppBox<ConstIterator>
Calls C++ function: QList<int>::const_iterator QList<int>::const_iterator::operator+(long long j) const
.
§type Output = CppBox<ConstIterator>
type Output = CppBox<ConstIterator>
+
operator.source§impl CppDeletable for ConstIterator
impl CppDeletable for ConstIterator
source§unsafe fn delete(&self)
unsafe fn delete(&self)
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
Calls C++ function: [destructor] void QList<int>::const_iterator::~const_iterator()
.
The QList::const_iterator class provides an STL-style const iterator for QList and QQueue.
QList provides both STL-style iterators and Java-style iterators. 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.
QList<T>::const_iterator allows you to iterate over a QList<T> (or a QQueue<T>). If you want to modify the QList as you iterate over it, use QList::iterator instead. It is generally good practice to use QList::const_iterator on a non-const QList as well, unless you need to change the QList through the iterator. Const iterators are slightly faster, and can improve code readability.
The default QList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QList function like QList::constBegin(), QList::constEnd(), or QList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list:
QList<QString> list; list.append(“January”); list.append(“February”); ... list.append(“December”);
QList<QString>::const_iterator i; for (i = list.constBegin(); i != list.constEnd(); ++i) cout << *i << endl;
Most QList functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QList. One place where STL-style iterators do make sense is as arguments to generic algorithms.
For example, here's how to delete all the widgets stored in a QList<QWidget *>:
QList<QWidget *> list; ... qDeleteAll(list.constBegin(), list.constEnd());
Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the QList will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use QLinkedList rather than QList.
Warning: 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 Implicit sharing iterator problem.
source§impl Decrement for ConstIterator
impl Decrement for ConstIterator
source§unsafe fn dec(&self) -> Ref<ConstIterator>
unsafe fn dec(&self) -> Ref<ConstIterator>
The prefix -- operator (--it
) makes the preceding item current and returns an iterator to the new current item.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator--()
.
The prefix – operator (–it
) makes the preceding item current and returns an iterator to the new current item.
Calling this function on QAssociativeIterable::begin() leads to undefined results.
See also operator++().
§type Output = Ref<ConstIterator>
type Output = Ref<ConstIterator>
source§impl Ge<Ref<ConstIterator>> for ConstIterator
impl Ge<Ref<ConstIterator>> for ConstIterator
source§unsafe fn ge(&self, other: &Ref<ConstIterator>) -> bool
unsafe fn ge(&self, other: &Ref<ConstIterator>) -> bool
Returns true
if the item pointed to by this iterator is greater than or equal to the item pointed to by the other iterator.
Calls C++ function: bool QList<int>::const_iterator::operator>=(const QList<int>::const_iterator& other) const
.
Returns true
if the item pointed to by this iterator is greater than or equal to the item pointed to by the other iterator.
source§impl Gt<Ref<ConstIterator>> for ConstIterator
impl Gt<Ref<ConstIterator>> for ConstIterator
source§unsafe fn gt(&self, other: &Ref<ConstIterator>) -> bool
unsafe fn gt(&self, other: &Ref<ConstIterator>) -> bool
Returns true
if the item pointed to by this iterator is greater than the item pointed to by the other iterator.
Calls C++ function: bool QList<int>::const_iterator::operator>(const QList<int>::const_iterator& other) const
.
Returns true
if the item pointed to by this iterator is greater than the item pointed to by the other iterator.
source§impl Increment for ConstIterator
impl Increment for ConstIterator
source§unsafe fn inc(&self) -> Ref<ConstIterator>
unsafe fn inc(&self) -> Ref<ConstIterator>
The prefix ++ operator (++it
) advances the iterator to the next item in the container and returns an iterator to the new current item.
Calls C++ function: QList<int>::const_iterator& QList<int>::const_iterator::operator++()
.
The prefix ++ operator (++it
) advances the iterator to the next item in the container and returns an iterator to the new current item.
Calling this function on QAssociativeIterable::end() leads to undefined results.
See also operator--().
§type Output = Ref<ConstIterator>
type Output = Ref<ConstIterator>
source§impl Indirection for ConstIterator
impl Indirection for ConstIterator
source§impl Le<Ref<ConstIterator>> for ConstIterator
impl Le<Ref<ConstIterator>> for ConstIterator
source§unsafe fn le(&self, other: &Ref<ConstIterator>) -> bool
unsafe fn le(&self, other: &Ref<ConstIterator>) -> bool
Returns true
if the item pointed to by this iterator is less than or equal to the item pointed to by the other iterator.
Calls C++ function: bool QList<int>::const_iterator::operator<=(const QList<int>::const_iterator& other) const
.
Returns true
if the item pointed to by this iterator is less than or equal to the item pointed to by the other iterator.
source§impl Lt<Ref<ConstIterator>> for ConstIterator
impl Lt<Ref<ConstIterator>> for ConstIterator
source§unsafe fn lt(&self, other: &Ref<ConstIterator>) -> bool
unsafe fn lt(&self, other: &Ref<ConstIterator>) -> bool
Returns true
if the item pointed to by this iterator is less than the item pointed to by the other iterator.
Calls C++ function: bool QList<int>::const_iterator::operator<(const QList<int>::const_iterator& other) const
.
Returns true
if the item pointed to by this iterator is less than the item pointed to by the other iterator.
source§impl PartialEq<Ref<ConstIterator>> for ConstIterator
impl PartialEq<Ref<ConstIterator>> for ConstIterator
source§fn eq(&self, o: &Ref<ConstIterator>) -> bool
fn eq(&self, o: &Ref<ConstIterator>) -> bool
Returns true
if other points to the same item as this iterator; otherwise returns false
.
Calls C++ function: bool QList<int>::const_iterator::operator==(const QList<int>::const_iterator& o) const
.
Returns true
if other points to the same item as this iterator; otherwise returns false
.
See also operator!=().
source§impl Sub<Ref<ConstIterator>> for &ConstIterator
impl Sub<Ref<ConstIterator>> for &ConstIterator
source§impl Sub<i64> for &ConstIterator
impl Sub<i64> for &ConstIterator
source§fn sub(self, j: c_longlong) -> CppBox<ConstIterator>
fn sub(self, j: c_longlong) -> CppBox<ConstIterator>
Calls C++ function: QList<int>::const_iterator QList<int>::const_iterator::operator-(long long j) const
.
§type Output = CppBox<ConstIterator>
type Output = CppBox<ConstIterator>
-
operator.