const_iterator 类

class QFuture ::const_iterator

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

该类在 Qt 4.4 引入。

所有成员列表，包括继承成员

注意： 此类的所有函数可重入 .

公共类型

typedef	difference_type
typedef	iterator_category
typedef	pointer
typedef	reference
typedef	value_type

公共函数

	const_iterator (const const_iterator & other )
	const_iterator ()
const_iterator &	operator= (const const_iterator & other )
bool	operator!= (const const_iterator & other ) const
const T &	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
const_iterator &	operator-- ()
const_iterator	operator-- ( int )
const_iterator &	operator-= (int j )
const T *	operator-> () const
bool	operator== (const const_iterator & other ) const

详细描述

QFuture provides both STL 样式迭代器 and Java 风格迭代器 . 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.

默认 QFuture::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QFuture function like QFuture::constBegin () 或 QFuture::constEnd () before you start iterating. Here's a typical loop that prints all the results available in a future:

QFuture<QString> future = ...;
QFuture<QString>::const_iterator i;
for (i = future.constBegin(); i != future.constEnd(); ++i)
    cout << *i << Qt::endl;

另请参阅 QFutureIterator and QFuture .

成员类型文档编制

typedef const_iterator:: difference_type

typedef 对于 ptrdiff_t。为兼容 STL 提供。

typedef const_iterator:: iterator_category

Typedef for std::bidirectional_iterator_tag. Provided for STL compatibility.

typedef const_iterator:: pointer

Typedef for const T *. Provided for STL compatibility.

typedef const_iterator:: reference

Typedef for const T &. Provided for STL compatibility.

typedef const_iterator:: value_type

typedef 对于 T。为兼容 STL 提供。

成员函数文档编制

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 iterartor. Use operator=() to assign a value to it before using it.

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

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

赋值 other to this iterator.

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

返回 true if other points to a different result than this iterator; otherwise returns false .

另请参阅 operator== ().

const T &const_iterator:: operator* () const

Returns the current result.

const_iterator const_iterator:: operator+ ( int j ) const

Returns an iterator to the results 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 result in the future and returns an iterator to the new current result.

Calling this function on QFuture <T>::constEnd() 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 result in the future and returns an iterator to the previously current result.

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

Advances the iterator by j results. (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 result at j positions backward from this iterator. (If j is negative, the iterator goes forward.)

另请参阅 operator+ () 和 operator-= ().

const_iterator &const_iterator:: operator-- ()

The prefix -- operator ( --it ) makes the preceding result current and returns an iterator to the new current result.

Calling this function on QFuture <T>::constBegin() 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 result current and returns an iterator to the previously current result.

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

Makes the iterator go back by j results. (If j is negative, the iterator goes forward.)

另请参阅 operator+= () 和 operator- ().

const T *const_iterator:: operator-> () const

Returns a pointer to the current result.

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

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

另请参阅 operator!= ().