Compilare: user.cpp: In constructor ‘trie::trie()’: user.cpp:12:36: 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 ‘int main()’: user.cpp:81:33: 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:82:35: 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); ^ /tmp/ccsEdV7H.o: In function `main': user.cpp:(.text.startup+0xcf): warning: the `gets' function is dangerous and should not be used.