Compilare: user.cpp: In function ‘bool log(std::string)’: user.cpp:29:10: warning: variable ‘ch’ set but not used [-Wunused-but-set-variable] char ch; ^ user.cpp: In function ‘int main()’: user.cpp:179:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l<s1.size()) ^ user.cpp:187:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l<s2.size()) ^