Compilare: user.cpp: In member function ‘void AhoCorasick::addWord(const string&, int)’: user.cpp:50:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size (); ++i) ^ user.cpp: In member function ‘void AhoCorasick::fin()’: user.cpp:99:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < states.size (); ++i) ^ user.cpp: In member function ‘void AhoCorasick::run(const string&)’: user.cpp:123:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size (); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:157:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < automaton.states.size (); ++i) ^ user.cpp:158:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < automaton.states[i].word.size (); ++j) ^ user.cpp:140:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("virus.in", "r", stdin); ^ user.cpp:141:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("virus.out", "w", stdout); ^