25 Iterators library [iterators]

25.6 Stream iterators [stream.iterators]

25.6.1 General [stream.iterators.general]

To make it possible for algorithmic templates to work directly with input/output streams, appropriate iterator-like class templates are provided.
[Example 1:
partial_sum(istream_iterator<double, char>(cin), istream_iterator<double, char>(), ostream_iterator<double, char>(cout, "\n")); reads a file containing floating-point numbers from cin, and prints the partial sums onto cout.
— end example]