const_iterator 类

class QJsonArray ::const_iterator

The QJsonArray::const_iterator 类提供 STL 样式 const 迭代器为 QJsonArray . 更多...

公共类型

typedef iterator_category

公共函数

const_iterator (const iterator & other )
const_iterator (const const_iterator & other )
const_iterator ()
bool operator!= (const const_iterator & other ) const
QJsonValue operator* () const
const_iterator operator+ (int j ) const
const_iterator & operator++ ()
const_iterator operator++ ( int )
const_iterator & operator+= (int j )
const_iterator operator- (int j ) const
int operator- (const_iterator other ) const
const_iterator & operator-- ()
const_iterator operator-- ( int )
const_iterator & operator-= (int j )
QJsonValue * operator-> () const
bool operator< (const const_iterator & other ) const
bool operator<= (const const_iterator & other ) const
bool operator== (const const_iterator & other ) const
bool operator> (const const_iterator & other ) const
bool operator>= (const const_iterator & other ) const
QJsonValue operator[] (int j ) const

详细描述

QJsonArray::const_iterator allows you to iterate over a QJsonArray . If you want to modify the QJsonArray as you iterate over it, use QJsonArray::iterator instead. It is generally a good practice to use QJsonArray::const_iterator on a non-const QJsonArray as well, unless you need to change the QJsonArray through the iterator. Const iterators are slightly faster and improves code readability.

默认 QJsonArray::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QJsonArray function like QJsonArray::constBegin (), QJsonArray::constEnd (),或 QJsonArray::insert () before you can start iterating.

Most QJsonArray functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QJsonArray . 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 QJsonArray will render all existing iterators undefined.

另请参阅 QJsonArray::iterator .

成员类型文档编制

typedef const_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

const_iterator:: const_iterator (const iterator & other )

构造副本为 other .

const_iterator:: const_iterator (const const_iterator & other )

构造副本为 other .

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.

另请参阅 QJsonArray::constBegin () 和 QJsonArray::constEnd ().

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

返回 true if other 指向与此迭代器不同的项;否则返回 false .

另请参阅 operator== ().

QJsonValue const_iterator:: operator* () const

返回当前项。

const_iterator const_iterator:: operator+ ( int j ) const

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

另请参阅 operator- () 和 operator+= ().

const_iterator &const_iterator:: operator++ ()

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

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

另请参阅 operator-- ().

const_iterator const_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.

const_iterator &const_iterator:: operator+= ( int j )

Advances the iterator by j items. If j is negative, the iterator goes backward.

另请参阅 operator-= () 和 operator+ ().

const_iterator const_iterator:: operator- ( int j ) const

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

另请参阅 operator+ () 和 operator-= ().

int const_iterator:: operator- ( const_iterator other ) const

Returns the number of items between the item pointed to by other and the item pointed to by this iterator.

const_iterator &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 QJsonArray::begin () leads to undefined results.

另请参阅 operator++ ().

const_iterator const_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.

const_iterator &const_iterator:: operator-= ( int j )

Makes the iterator go back by j items. If j is negative, the iterator goes forward.

另请参阅 operator+= () 和 operator- ().

QJsonValue *const_iterator:: operator-> () const

Returns a pointer to the current item.

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

返回 true if the item pointed to by this iterator is less than the item pointed to by the other iterator.

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

返回 true if the item pointed to by this iterator is less than or equal to the item pointed to by the other iterator.

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

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

另请参阅 operator!= ().

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

返回 true if the item pointed to by this iterator is greater than the item pointed to by the other iterator.

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

返回 true if the item pointed to by this iterator is greater than or equal to the item pointed to by the other iterator.

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.

另请参阅 operator+ ().