std::istream_iterator<T,CharT,Traits,Distance>::istream_iterator (3) - Linux Manuals

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

NAME

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

Synopsis

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