Borderou de evaluare (job #110212)

Eroare de compilare: user.cpp: In function ‘void back(int, int, int*)’: user.cpp:12:9: error: no match for ‘operator<’ in ‘g.std::basic_ofstream<char>::<anonymous>.std::basic_ostream<_CharT, _Traits>::operator<< [with _CharT = char, _Traits = std::char_traits<char>]((*(v + ((unsigned int)(((unsigned int)i) * 4u))))) < " "’ user.cpp:12:9: note: candidates are: user.cpp:12:9: note: operator<(const char*, const char*) <built-in> user.cpp:12:9: note: no known conversion for argument 1 from ‘std::basic_ostream<char>’ to ‘const char*’ user.cpp:12:9: note: operator<(void*, void*) <built-in> user.cpp:12:9: note: no known conversion for argument 2 from ‘const char [2]’ to ‘void*’ /usr/include/c++/4.6/bits/stl_pair.h:207:5: note: template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&) /usr/include/c++/4.6/bits/stl_iterator.h:291:5: note: template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&) /usr/include/c++/4.6/bits/stl_iterator.h:341:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::reverse_iterator<_IteratorL>&, const std::reverse_iterator<_IteratorR>&) /usr/include/c++/4.6/bits/stl_iterator.h:1049:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorR>&) /usr/include/c++/4.6/bits/stl_iterator.h:1055:5: note: template<class _Iterator> bool std::operator<(const std::move_iterator<_Iterator>&, const std::move_iterator<_Iterator>&) /usr/include/c++/4.6/bits/basic_string.h:2510:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const std::basic_string<_CharT, _Traits, _Alloc>&) /usr/include/c++/4.6/bits/basic_string.h:2522:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*) /usr/include/c++/4.6/bits/basic_string.h:2534:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const std::basic_string<_CharT, _Traits, _Alloc>&) user.cpp: In function ‘int main()’: user.cpp:30:7: warning: unused variable ‘j’ [-Wunused-variable]