Compilare: user.cpp: In function ‘void Insert(int, int)’: user.cpp:22:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < H[key].size(); ++i) ^ user.cpp: In function ‘int Check(int, int)’: user.cpp:36:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < H[key].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:46:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("enigma.in", "r", stdin); ^ user.cpp:47:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("enigma.out", "w", stdout); ^ user.cpp:48:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("debug.err", "w", stderr); ^