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| Category: iterators | | Component type: type |
Description
An istream_iterator is an InputIterator that performs formatted input of objects of type T from a particular istream. When end of stream is reached, the istream_iterator takes on a special end of stream value, which is a past-the-end iterator. Note that all of the restrictions of an InputIterator must be obeyed, including the restrictions on the ordering of operator* and operator++ operations.
Example
Fill a Vector with values read from standard input.
Vector<int> V;
copy(istream_iterator<int>(cin), istream_iterator<int>(),
back_insert_iterator(V));
Definition
Defined in the standard header iterator, and in the nonstandard backward-compatibility header iterator.h.
Template parameters
| Parameter | Description | Default |
T | The istream_iterator's value type. Operator* returns a const T&. | |
Distance | The istream_iterator's distance type. | ptrdiff_t |
Model of
InputIterator
Type requirements
The value type T must be a type such that cin >> T is a valid expression.
The value type T must be a model of DefaultConstructible.
The distance type must, as described in the InputIterator requirements, be a signed integral type.
Public base classes
None.
Members
| Member | Where defined | Description |
istream_iterator() | istream_iterator | See below. |
istream_iterator(istream&) | istream_iterator | See below. |
istream_iterator(const istream_iterator&) | trivial | The copy constructor |
istream_iterator& operator=(const istream_iterator&) | trivial | The assignment operator |
const T& operator*() const | InputIterator | Returns the next object in the stream. |
istream_iterator& operator++() | InputIterator | Preincrement. |
istream_iterator& operator++(int) | InputIterator | Postincrement. |
bool operator==(const istream_iterator&, const istream_iterator&) | trivial | The equality operator. This is a global function, not a member function. |
input_iterator_tag iterator_category(const istream_iterator&) | iterator_tags | Returns the iterator's category. |
T* value_type(const istream_iterator&) | iterator_tags | Returns the iterator's value type. |
Distance* distance_type(const istream_iterator&) | iterator_tags | Returns the iterator's distance type. < |
New members
These members are not defined in the InputIterator requirements, but are specific to istream_iterator.
| Function | Description |
istream_iterator() | The default constructor: Constructs an end-of-stream iterator. This is a past-the-end iterator, and it is useful when constructing a "range". |
istream_iterator(istream& s) | Creates an istream_iterator that reads values from the input stream s. When s reaches end of stream, this iterator will compare equal to an end-of-stream iterator created using the default constructor. |
Notes
See also
ostream_iterator, InputIterator, OutputIterator.
