(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) |
auto x = T();
is a constant initializer (since C++11).stream
in a data member, and performs the first read from the input stream to initialize the cached value data member.other
. If std::is_trivially_copy_constructible<T>::value
is true
, this copy constructor is a trivial copy constructor. (since C++11)
stream | - | stream to initialize the istream_iterator with |
other | - | another istream_iterator of the same type |
#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
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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