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

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C++
Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
(C++20)
(C++20)
(C++20)
Utilities
(C++20)
Iterator adaptors
Range access
(C++11)(C++14)
(C++14)(C++14)
(C++11)(C++14)
(C++14)(C++14)
(C++17)(C++20)
(C++17)
(C++17)
std::istream_iterator
(1)
istream_iterator();
 (until C++11)
constexpr istream_iterator();
 (since C++11)
constexpr istream_iterator( std::default_sentinel_t ) ;
(2) (since C++20)
istream_iterator( istream_type& stream );
 (3)
(4)
istream_iterator( const istream_iterator& other );
 (until C++11)
istream_iterator( const istream_iterator& other ) = default ;
(since C++11)
1,2) Constructs the end-of-stream iterator , value-initializes the stored value. This constructor is constexpr if the initializer in the definition auto x = T(); (since C++11)
3) Initializes the iterator, stores the address of stream
4) Constructs a copy of other. If std::is_trivially_copy_constructible <T> :: value is true (since C++11)

Parameters

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

Example

Run this code
#include <algorithm>
#include <iostream>
#include <iterator>
#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

Defect reports

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

DR Applied to Behavior as published Correct behavior
LWG 1280 C++98 overload (3) stored stream directly stores its address instead
P0738R2 C++98 the first read might be deferred to the first dereference always performed in the constructor
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