Compilare: user.cpp: In function ‘int main()’: user.cpp:60:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == A.size()) { ^ user.cpp:71:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < matches.size(); ++ i) { ^ user.cpp:39:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in", "r", stdin); ^ user.cpp:40:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out", "w", stdout); ^