Compilare: user.cpp: In static member function ‘static void Trie::add(const string&, Trie*, int)’: user.cpp:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(indx == s.size()) { ^ user.cpp: In static member function ‘static bool Trie::del(const string&, Trie*, int)’: user.cpp:46:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (indx == s.size()) ^ user.cpp: In static member function ‘static int Trie::freq(const string&, Trie*, int)’: user.cpp:76:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(indx == s.size()) ^ user.cpp: In static member function ‘static int Trie::prefix(const string&, Trie*, int)’: user.cpp:89:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(indx == s.size()) ^