Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:55:25: error: no match for ‘operator==’ (operand types are ‘punct’ and ‘punct’) if (v[stack[i]] == b) break; ^ user.cpp:55:25: note: candidates are: In file included from /usr/local/include/c++/4.8.0/bits/stl_algo.h:66:0, from /usr/local/include/c++/4.8.0/algorithm:62, from user.cpp:2: /usr/local/include/c++/4.8.0/functional:2540:5: note: template<class _Res, class ... _Args> bool std::operator==(std::nullptr_t, const std::function<_Res(_ArgTypes ...)>&) operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept ^ /usr/local/include/c++/4.8.0/functional:2540:5: note: template argument deduction/substitution failed: user.cpp:55:28: note: cannot convert ‘v[stack[i]]’ (type ‘punct’) to type ‘std::nullptr_t’ if (v[stack[i]] == b) break; ^ In file included from /usr/local/include/c++/4.8.0/bits/stl_algo.h:66:0, from /usr/local/include/c++/4.8.0/algorithm:62, from user.cpp:2: /usr/local/include/c++/4.8.0/functional:2534:5: note: template<class _Res, class ... _Args> bool std::operator==(const std::function<_Res(_ArgTypes ...)>&, std::nullptr_t) operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept ^ /usr/local/include/c++/4.8.0/functional:2534:5: note: template argument deduction/substitution failed: user.cpp:55:28: note: ‘punct’ is not derived from ‘const std::function<_Res(_ArgTypes ...)>’ if (v[stack[i]] == b) break; ^ In file included from /usr/local/include/c++/4.8.0/functional:55:0, from /usr/local/include/c++/4.8.0/bits/stl_algo.h:66, from /usr/local/include/c++/4.8.0/algorithm:62, from user.cpp:2: /usr/local/include/c++/4.8.0/tuple:811:5: note: template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const std::tuple<_Elements ...>&, const std::tuple<_Elements ...>&) operator==(const tuple<_TElements...>& __t, ^ /usr/local/include/c++/4.8.0/tuple:811:5: note: template argument deduction/substitution failed: user.cpp:55:28: note: ‘punct’ is not derived from ‘const std::tuple<_Elements ...>’ if (v[stack[i]] == b) break; ^ In file included from /usr/local/include/c++/4.8.0/tuple:39:0, from /usr/local/include/c++/4.8.0/functional:55, from /usr/local/include/c++/4.8.0/bits/stl_algo.h:66, from /usr/local/include/c++/4.8.0/algorithm:62, from user.cpp:2: /usr/local/include/c++/4.8.0/array:228:5: note: template<class _Tp, unsigned int _Nm> bool std::operator==(const std::array<_Tp, _Nm>&, const std::array<_Tp, _Nm>&) operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two) ^ /usr/local/include/c++/4.8.0/array:228:5: note: template argument deduction/substitution failed: user.cpp:55:28: note: ‘punct’ is not derived from ‘const std::array<_Tp, _Nm>’ if (v[stack[i]] == b) break; ^ In file included from /usr/local/include/c++/4.8.0/random:52:0, from /usr/local/include/c++/4.8.0/bits/stl_algo.h:65,