Compilare: user.cpp: In member function ‘void Trie::_insert(char*)’: user.cpp:26:16: warning: NULL used in arithmetic [-Wpointer-arith] if (*word == NULL) { ^ user.cpp: In member function ‘int Trie::_count(char*)’: user.cpp:39:16: warning: NULL used in arithmetic [-Wpointer-arith] if (*word == NULL) { ^ user.cpp: In member function ‘bool Trie::_erase(char*)’: user.cpp:51:16: warning: NULL used in arithmetic [-Wpointer-arith] if (*word == NULL) { ^ user.cpp: In member function ‘int Trie::lgPrefix(char*, int)’: user.cpp:84:16: warning: NULL used in arithmetic [-Wpointer-arith] if (*word == NULL) { ^ user.cpp: In member function ‘bool Trie::_erase(char*)’: user.cpp:81:2: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In member function ‘int Trie::_count(char*)’: user.cpp:48:2: warning: control reaches end of non-void function [-Wreturn-type] } ^