Iterator 类

class QCborArray ::Iterator

The QCborArray::Iterator 类提供 STL 样式非常量迭代器为 QCborArray . 更多...

该类在 Qt 5.12 引入。

公共类型

typedef iterator_category

公共函数

Iterator (const Iterator & other )
Iterator ()
Iterator & operator= (const Iterator & other )
bool operator!= (const Iterator & other ) const
bool operator!= (const ConstIterator & other ) const
QCborValueRef operator* () const
迭代器 operator+ (qsizetype j ) const
Iterator & operator++ ()
迭代器 operator++ ( int )
Iterator & operator+= (qsizetype j )
迭代器 operator- (qsizetype j ) const
qsizetype operator- (Iterator other ) const
Iterator & operator-- ()
迭代器 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
QCborValueRef operator[] (qsizetype j )

详细描述

QCborArray::Iterator allows you to iterate over a QCborArray and to modify the array item associated with the iterator. If you want to iterate over a const QCborArray ,使用 QCborArray::ConstIterator instead. It is generally a good practice to use QCborArray::ConstIterator on a non-const QCborArray as well, unless you need to change the QCborArray through the iterator. Const iterators are slightly faster and improve code readability.

Iterators are initialized by using a QCborArray function like QCborArray::begin (), QCborArray::end (),或 QCborArray::insert (). Iteration is only possible after that.

Most QCborArray functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QCborArray . One place where STL-style iterators do make sense is as arguments to 一般算法 .

Multiple iterators can be used on the same array. However, be aware that any non-const function call performed on the QCborArray will render all existing iterators undefined.

另请参阅 QCborArray::ConstIterator .

成员类型文档编制

typedef Iterator:: iterator_category

同义词 std::random_access_iterator_tag indicating this iterator is a random access iterator.

成员函数文档编制

bool Iterator:: operator>= (const ConstIterator & other ) const

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

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

bool Iterator:: operator> (const ConstIterator & other ) const

bool Iterator:: operator> (const Iterator & other ) const

返回 true if the entry in the array pointed to by this iterator occurs after the entry pointed to by the other iterator.

bool Iterator:: operator<= (const ConstIterator & other ) const

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

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

bool Iterator:: operator< (const ConstIterator & other ) const

bool Iterator:: operator< (const Iterator & other ) const

返回 true if the entry in the array pointed to by this iterator occurs before the entry pointed to by the other iterator.

bool Iterator:: operator!= (const ConstIterator & other ) const

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

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

另请参阅 operator== ().

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

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

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

另请参阅 operator!= ().

Iterator:: Iterator (const Iterator & other )

制作副本为 other .

Iterator:: 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.

另请参阅 QCborArray::begin () 和 QCborArray::end ().

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

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

QCborValueRef Iterator:: operator* () const

Returns a modifiable reference to the current item.

You can change the value of an item by using operator*() 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.

迭代器 Iterator:: operator+ ( qsizetype j ) const

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

另请参阅 operator- () 和 operator+= ().

迭代器 &Iterator:: operator++ ()

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

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

另请参阅 operator-- ().

迭代器 Iterator:: operator++ ( int )

这是重载函数。

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

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

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

另请参阅 operator-= () 和 operator+ ().

迭代器 Iterator:: operator- ( qsizetype j ) const

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

另请参阅 operator+ () 和 operator-= ().

qsizetype Iterator:: operator- ( Iterator other ) const

Returns the offset of this iterator relative to other .

迭代器 &Iterator:: operator-- ()

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

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

另请参阅 operator++ ().

迭代器 Iterator:: operator-- ( int )

这是重载函数。

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

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

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

另请参阅 operator+= () 和 operator- ().

QCborValueRef *Iterator:: operator-> () const

Returns a pointer to a modifiable reference to the current item.

QCborValueRef Iterator:: operator[] ( qsizetype j )

Returns a modifiable reference to the item at a position j steps forward from the item pointed to by this iterator.

This function is provided to make QCborArray iterators behave like C++ pointers.

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.

另请参阅 operator+ ().