Compilare: user.cpp: In function ‘int cost_muc(std::string)’: user.cpp:21:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.length(); ++i, p5 *= 5) ^ user.cpp: In function ‘int cost_muc_real(std::string)’: user.cpp:31:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.length(); ++i, p5 *= 5) ^