Compilare: user.cpp: In function ‘bool is_csir(std::string)’: user.cpp:17:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < s.size(); ++j) ^ user.cpp:25:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < s.size(); ++j) ^ user.cpp:41:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (poz < s.size()) { ^ user.cpp:31:18: warning: unused variable ‘begin’ [-Wunused-variable] int poz = 0, begin = 0; ^