Eroare de compilare: In file included from /usr/include/c++/4.4/algorithm:62, from user.cpp:3: /usr/include/c++/4.4/bits/stl_algo.h: In function ‘const _Tp& std::__median(const _Tp&, const _Tp&, const _Tp&, _Compare) [with _Tp = Carnat, _Compare = int (*)(Carnat&, Carnat&)]’: /usr/include/c++/4.4/bits/stl_algo.h:2301: instantiated from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = Carnat*, _Size = int, _Compare = int (*)(Carnat&, Carnat&)]’ /usr/include/c++/4.4/bits/stl_algo.h:5258: instantiated from ‘void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = Carnat*, _Compare = int (*)(Carnat&, Carnat&)]’ user.cpp:48: instantiated from here /usr/include/c++/4.4/bits/stl_algo.h:124: error: invalid initialization of reference of type ‘Carnat&’ from expression of type ‘const Carnat’ /usr/include/c++/4.4/bits/stl_algo.h:125: error: invalid initialization of reference of type ‘Carnat&’ from expression of type ‘const Carnat’ /usr/include/c++/4.4/bits/stl_algo.h:127: error: invalid initialization of reference of type ‘Carnat&’ from expression of type ‘const Carnat’ /usr/include/c++/4.4/bits/stl_algo.h:131: error: invalid initialization of reference of type ‘Carnat&’ from expression of type ‘const Carnat’ /usr/include/c++/4.4/bits/stl_algo.h:133: error: invalid initialization of reference of type ‘Carnat&’ from expression of type ‘const Carnat’