Compilare: user.cpp: In function ‘int main()’: user.cpp:44:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in", "r", stdin); ^ user.cpp:45:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out", "w", stdout); ^ user.cpp:53:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %s", &operation_type, ch_word); ^ user.cpp: In function ‘void trie_erase(std::string)’: user.cpp:132:43: warning: ‘letters_index’ may be used uninitialized in this function [-Wmaybe-uninitialized] ante_current->next[letters_index] = NULL; ^