Iterator Class

class QCborMap::Iterator

The QCborMap::Iterator class provides an STL-style non-const iterator for QCborMap. More...

This class was introduced in Qt 5.12.

• List of all members, including inherited members

Public Types

iterator_category

Public Functions

	Iterator(const Iterator &other)
	Iterator()
Iterator &	operator=(const Iterator &other)
QCborValue	key() const
QCborValueRef	value() const
bool	operator!=(const Iterator &other) const
bool	operator!=(const ConstIterator &other) const
Iterator::value_type	operator*() const
Iterator	operator+(qsizetype j) const
Iterator &	operator++()
Iterator	operator++(int)
Iterator &	operator+=(qsizetype j)
Iterator	operator-(qsizetype j) const
qsizetype	operator-(Iterator j) const
Iterator &	operator--()
Iterator	operator--(int)
Iterator &	operator-=(qsizetype j)
QCborValueRef *	operator->() const
bool	operator<(const Iterator &other) const
bool	operator<(const ConstIterator &other) const
bool	operator<=(const Iterator &other) const
bool	operator<=(const ConstIterator &other) const
bool	operator==(const Iterator &other) const
bool	operator==(const ConstIterator &other) const
bool	operator>(const Iterator &other) const
bool	operator>(const ConstIterator &other) const
bool	operator>=(const Iterator &other) const
bool	operator>=(const ConstIterator &other) const

Detailed Description

QCborMap::Iterator allows you to iterate over a QCborMap and to modify the value (but not the key) stored under a particular key. If you want to iterate over a const QCborMap, you should use QCborMap::ConstIterator. It is generally good practice to use QCborMap::ConstIterator on a non-const QCborMap as well, unless you need to change the QCborMap through the iterator. Const iterators are slightly faster, and improve code readability.

You must initialize the iterator using a QCborMap function like QCborMap::begin(), QCborMap::end(), or QCborMap::find() before you can start iterating..

Multiple iterators can be used on the same object. Existing iterators will however become dangling once the object gets modified.

See also QCborMap::ConstIterator.

Member Type Documentation

Iterator::iterator_category

A synonym for std::random_access_iterator_tag indicating this iterator is a random-access iterator.

Member Function Documentation

Returns true if the entry in the map pointed to by this iterator occurs after or is the same entry as is pointed to by the other iterator.

Returns true if the entry in the map pointed to by this iterator occurs after the entry pointed to by the other iterator.

Returns true if the entry in the map pointed to by this iterator occurs before or is the same entry as is pointed to by the other iterator.

Returns true if the entry in the map pointed to by this iterator occurs before the entry pointed to by the other iterator.

Returns true if other points to a different entry in the map than this iterator; otherwise returns false.

See also operator==().

Returns true if other points to the same entry in the map as this iterator; otherwise returns false.

See also operator!=().

Iterator::Iterator(const Iterator &other)

Constructs an iterator as a copy of other.

Iterator::Iterator()

Constructs an uninitialized iterator.

Functions like key(), value(), and operator++() must not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it.

See also QCborMap::begin() and QCborMap::end().

Iterator &Iterator::operator=(const Iterator &other)

Makes this iterator a copy of other and returns a reference to this iterator.

QCborValue Iterator::key() const

Returns the current item's key.

There is no direct way of changing an item's key through an iterator, although it can be done by calling QCborMap::erase() followed by QCborMap::insert().

See also value().

QCborValueRef Iterator::value() const

Returns a modifiable reference to the current item's value.

You can change the value for a key by using value() on the left side of an assignment.

The return value is of type QCborValueRef, a helper class for QCborArray and QCborMap. When you get an object of type QCborValueRef, you can use it as if it were a reference to a QCborValue. If you assign to it, the assignment will apply to the element in the QCborArray or QCborMap from which you got the reference.

See also key() and operator*().

Iterator::value_type Iterator::operator*() const

Returns a pair containing the current item's key and a modifiable reference to the current item's value.

The second element of the pair is of type QCborValueRef, a helper class for QCborArray and QCborMap. When you get an object of type QCborValueRef, you can use it as if it were a reference to a QCborValue. If you assign to it, the assignment will apply to the element in the QCborArray or QCborMap from which you got the reference.

See also key() and value().

Iterator Iterator::operator+(qsizetype j) const

Returns an iterator to the item at j positions forward from this iterator. If j is negative, the iterator goes backward.

See also operator-().

Iterator &Iterator::operator++()

The prefix ++ operator, ++i, advances the iterator to the next item in the map and returns this iterator.

Calling this function on QCborMap::end() leads to undefined results.

See also operator--().

Iterator Iterator::operator++(int)

This is an overloaded function.

The postfix ++ operator, i++, advances the iterator to the next item in the map and returns an iterator to the previously current item.

Iterator &Iterator::operator+=(qsizetype j)

Advances the iterator by j items. If j is negative, the iterator goes backward. Returns a reference to this iterator.

See also operator-=() and operator+().

Iterator Iterator::operator-(qsizetype j) const

Returns an iterator to the item at j positions backward from this iterator. If j is negative, the iterator goes forward.

See also operator+().

qsizetype Iterator::operator-(Iterator j) const

Returns the position of the item at iterator j relative to the item at this iterator. If the item at j is forward of this time, the returned value is negative.

See also operator+().

Iterator &Iterator::operator--()

The prefix -- operator, --i, makes the preceding item current and returns this iterator.

Calling this function on QCborMap::begin() leads to undefined results.

See also operator++().

Iterator Iterator::operator--(int)

This is an overloaded function.

The postfix -- operator, i--, makes the preceding item current and returns an iterator pointing to the previously current item.

Iterator &Iterator::operator-=(qsizetype j)

Makes the iterator go back by j items. If j is negative, the iterator goes forward. Returns a reference to this iterator.

See also operator+=() and operator-().

QCborValueRef *Iterator::operator->() const

Returns a pointer to a modifiable reference to the current pair's value.