Użytkownik Krzysztof Żelechowski napisał:
The documentation for mismatch, as applied to ranges, says that rng2 must be at least as long as rng1. Why is this precondition necessary? The precondition is impossible to evaluate for bare input iterators without destroying the iterators, whereupon it is impossible to call mismatch any more.
IMHO, it would be perfectly reasonable to stop at the end of rng2 if rng2 is shorter.
<URL: http://www.boost.org/doc/libs/1_47_0/libs/range/ doc/html/range/reference/algorithms/non_mutating/mismatch.html>
I am steering towards the following invocation: ::boost:: mismatch (array, :;std:: cin, eq_int_type); OTOH, it is possible, although more troublesome than it should be, to use a modified input stream buffer iterator that does returns int_type and does not fail (Listing#1). However, that begs the question how the second range argument should be constructed, since the end of the second range is ignored anyway. My solution, pseudorange, is in Listing#2, and my invocation becomes (with obvious abbreviations) ::boost:: mismatch (array | transformed (to_int_type), pseudorange < iterator_oo > (:;std:: cin), eq_int_type); Note that the fact that iterator_oo () is a valid end iterator for an input stream buffer is accidental, and pseudorange < char const * > will also work provided the length prerequisite is met somehow. My OP suggests that you are not doing ::boost:: mismatch right; however, temporarily assuming that the bug is here to stay since noone considered it worth answering, am I doing it right? Chris == Listing#1 == template < class P_C, class P_T = typename ::std:: istreambuf_iterator < P_C > > class istreambuf_iterator_oo { public: typedef P_T inherited; public: typedef P_C char_type; public: typedef typename inherited:: traits_type traits_type_; public: typedef typename inherited:: int_type int_type_; public: typedef ::std:: iterator < typename inherited:: iterator_category, int_type_, typename inherited:: difference_type, typename inherited:: pointer, typename inherited:: reference > iter_; public: class I: public iter_ { public: typedef int_type_ int_type; public: typedef traits_type_ traits_type; public: typedef typename traits_type:: char_type char_type; public: static int_type eof (void) { return traits_type:: eof (); } public: static int_type promote (char_type const &p_c) { return traits_type:: to_int_type (p_c); } public: I (void): it () {} public: I (inherited const &p_it): inherited (p_it) {} public: typedef typename inherited:: istream_type istream_type; public: I (istream_type &p_it): it (p_it) {} public: operator inherited const & () const { return it; } public: inherited const & value (void) const { return it; } public: int_type operator* (void) const { return it == inherited ()? eof (): promote (*it); } int equal (inherited const &p) const { return it. equal (p); } public: I &operator ++ (void) { if (it != inherited ()) ++it; return *this; } protected: inherited it; }; }; == Listing#2 == template < class P_I > struct pseudorange { typedef P_I iterator, const_iterator; iterator begin () const { return m_; } iterator end () const { return iterator (); } iterator m_; pseudorange (iterator const &p_): m_ (p_) {} };