Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:51:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < cells.size(); ++ i) { ^ In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:2: /usr/include/c++/4.8/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Celula*, std::vector<Celula> >; _Tp = Celula]’: /usr/include/c++/4.8/bits/stl_algo.h:2307:70: required from ‘_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Celula*, std::vector<Celula> >]’ /usr/include/c++/4.8/bits/stl_algo.h:2338:54: required from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Celula*, std::vector<Celula> >; _Size = int]’ /usr/include/c++/4.8/bits/stl_algo.h:5475:36: required from ‘void std::sort(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<Celula*, std::vector<Celula> >]’ user.cpp:48:36: required from here /usr/include/c++/4.8/bits/stl_algo.h:2266:20: error: no match for ‘operator<’ (operand types are ‘Celula’ and ‘const Celula’) while (*__first < __pivot) ^ /usr/include/c++/4.8/bits/stl_algo.h:2266:20: note: candidates are: user.cpp:9:10: note: bool Celula::operator<(Celula&) const bool operator < (Celula &other) const { ^ user.cpp:9:10: note: no known conversion for argument 1 from ‘const Celula’ to ‘Celula&’ In file included from /usr/include/c++/4.8/utility:70:0, from /usr/include/c++/4.8/algorithm:60, from user.cpp:2: /usr/include/c++/4.8/bits/stl_pair.h:220:5: note: template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&) operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) ^ /usr/include/c++/4.8/bits/stl_pair.h:220:5: note: template argument deduction/substitution failed: In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:2: /usr/include/c++/4.8/bits/stl_algo.h:2266:20: note: ‘Celula’ is not derived from ‘const std::pair<_T1, _T2>’ while (*__first < __pivot) ^ In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0, from /usr/include/c++/4.8/algorithm:61, from user.cpp:2: /usr/include/c++/4.8/bits/stl_iterator.h:297:5: note: template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&) operator<(const reverse_iterator<_Iterator>& __x, ^ /usr/include/c++/4.8/bits/stl_iterator.h:297:5: note: template argument deduction/substitution failed: In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:2: /usr/include/c++/4.8/bits/stl_algo.h:2266:20: note: ‘Celula’ is not derived from ‘const std::reverse_iterator<_Iterator>’ while (*__first < __pivot) ^ In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0, from /usr/include/c++/4.8/algorithm:61, from user.cpp:2: /usr/include/c++/4.8/bits/stl_iterator.h:347:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&) operator<(const reverse_iterator<_IteratorL>& __x, ^ /usr/include/c++/4.8/bits/stl_iterator.h:347:5: note: template argument deduction/substitution failed: