Eroare de compilare: user.cpp: In function 'int main()': user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp:25: warning: comparison between signed and unsigned integer expressions user.cpp:29: error: no matching function for call to 'std::vector<int, std::allocator<int> >::pop_back(int&)' /usr/include/c++/4.2/bits/stl_vector.h:618: note: candidates are: void std::vector<_Tp, _Alloc>::pop_back() [with _Tp = int, _Alloc = std::allocator<int>] user.cpp:33: warning: comparison between signed and unsigned integer expressions