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std::istream_iterator<T,CharT,Traits,Distance>::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(); is a constant initializer (since C++11).
3) 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.
4) Constructs a copy of other. If std::is_trivially_copy_constructible<T>::value is true, this copy constructor is a trivial copy constructor. (since C++11)

Parameters

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

Examples

#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

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

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