Iterator Class

Class Iterator is declared in class QCborMap.

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

This class was introduced in Qt 5.12.

Public Types

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

typedef Iterator::iterator_category

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

Member Function Documentation

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.

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