Compilare: user.cpp: In function ‘int main()’: user.cpp:16:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1;i<s.size();++i) ^ user.cpp:22:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=Sz+1;i<s.size();++i) ^