Compilare: user.cpp: In function ‘bool limita(char)’: user.cpp:21:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<=lim.size();++j) ^ user.cpp: In function ‘int main()’: user.cpp:31:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=s.size();++i) ^