Compilare: user.cpp: In member function ‘void aho_corasick_automaton::add_word(const string&, int)’: user.cpp:59:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); ++i) ^ user.cpp: In member function ‘void aho_corasick_automaton::build_fails(int)’: user.cpp:83:65: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(k && !states[k].transitions[states[nod].letter]) ^ user.cpp:90:56: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(states[k].transitions[states[nod].letter]) ^ user.cpp:91:59: warning: array subscript has type ‘char’ [-Wchar-subscripts] k=states[k].transitions[states[nod].letter]; ^ user.cpp: In member function ‘int aho_corasick_automaton::run_automaton(const string&)’: user.cpp:107:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); ++i) ^ user.cpp:117:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<states[aux].word.size(); ++j) ^ user.cpp:105:18: warning: unused variable ‘aux’ [-Wunused-variable] int k=0, aux; ^ user.cpp:121:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:128:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.in", "r", stdin); ^ user.cpp:129:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.out", "w", stdout); ^ user.cpp:133:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^