Compilare: user.cpp: In function ‘bool cuv(char)’: user.cpp:11:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=lim.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:23:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=s.size();i++) ^ user.cpp:27:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=s.size();i++) ^