understanding equality from istream_iterator

Question

Can someone please explain why this istream_iterator code.

// code extract from SGI STL istream_iterator class
bool _M_equal(const istream_iterator& __x) const {
   return (_M_ok == __x.M_ok) && (!_M_ok || _M_stream == __x._M_stream);
}

works and is not just written as

bool _M_equal(const istream_iterator& __x) const {
   return (_M_ok == __x.M_ok) && (_M_stream == __x._M_stream);
}

I don't understanding the reason for including !_M_ok. Thanks in advance.

Caleth · Accepted Answer · 2019-05-30 08:44:45Z

1

_M_stream == __x._M_stream has undefined behaviour if either _M_ok or __x._M_ok is false.

answered May 30, 2019 at 8:44

Caleth

66k2 gold badges53 silver badges101 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

understanding equality from istream_iterator

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related