Compilare: user.cpp: In function ‘void Z(int*, std::string, const string&)’: user.cpp:16:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < s.size() && s[i] == s[i-1]; ++i, ++z[1]); ^ user.cpp:18:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 2; i < s.size(); ++i) ^ user.cpp:24:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(dr < s.size() && s[dr] == s[dr-i]) ^ user.cpp:28:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = pattern.size(); i < z.size(); ++i) ^