std::istream_iterator<T,CharT,Traits,Distance>::istream_iterator

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Iterator library

Iterator primitives
iterator_traits
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag
iterator
Iterator adaptors
reverse_iterator move_iterator (C++11) back_insert_iterator front_insert_iterator insert_iterator	make_reverse_iterator (C++14) make_move_iterator (C++11) back_inserter front_inserter inserter
Stream iterators
istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
Iterator operations
advance
distance
prev (C++11)
next (C++11)
Range access
begincbegin (C++11)(C++14)
endcend (C++11)(C++14)
rbegincrbegin (C++14)(C++14)
rendcrend (C++14)(C++14)
Container access
sizessize (C++17)(C++20)
empty (C++17)
data (C++17)

 

std::istream_iterator

Member functions

istream_iterator::istream_iterator

istream_iterator::~istream_iterator

istream_iterator::operator*istream_iterator::operator->

istream_iterator::operator++istream_iterator::operator++(int)

Non-member functions

operator==operator!=

 

constexpr istream_iterator();	(1)
istream_iterator( istream_type& stream );	(2)
istream_iterator( const istream_iterator& other ) = default;	(3)

1) Constructs the end-of-stream iterator, value-initializes the stored value. This constructor is constexpr if the initializer in the definition auto x = T(); is a constant initializer.

2) Initializes the iterator, stores the address of stream in a data member, and performs the first read from the input stream to initialize the cached value data member.

3) Constructs a copy of other. If std::is_trivially_copy_constructible_v<T> is true , this copy constructor is a trivial copy constructor.

Parameters

stream	-	stream to initialize the istream_iterator with
other	-	another istream_iterator of the same type

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
P0738R2	C++98	the first read may be deferred to the first dereferencing	the first read is performed in the constructor

Examples

Run this code

#include <iostream>
#include <iterator>
#include <algorithm>
#include <sstream>
int main()
{
    std::istringstream stream("1 2 3 4 5");
    std::copy(
        std::istream_iterator<int>(stream),
        std::istream_iterator<int>(),
        std::ostream_iterator<int>(std::cout, " ")
    );
}

Output:

1 2 3 4 5