Compilare: user.cpp: In constructor ‘Trie::Trie()’: user.cpp:9:38: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(fiu, NULL, sizeof(fiu)); ^ user.cpp: In function ‘void add(Trie*, char*)’: user.cpp:18:14: warning: NULL used in arithmetic [-Wpointer-arith] if(*s == NULL) return ; ^~~~ user.cpp: In function ‘int main()’: user.cpp:27:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dictree.in", "r", stdin); ^ user.cpp:28:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dictree.out", "w", stdout); ^ user.cpp:30:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:33:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s); ^