Compilare: main.cpp: In function 'void Insert(Trie*, char*)': main.cpp:22:15: warning: NULL used in arithmetic [-Wpointer-arith] if(*word==NULL) ^~~~ main.cpp: In function 'void Erase(Trie*, char*)': main.cpp:34:15: warning: NULL used in arithmetic [-Wpointer-arith] if(*word==NULL) ^~~~ main.cpp: In function 'int CountApparition(Trie*, char*)': main.cpp:43:15: warning: NULL used in arithmetic [-Wpointer-arith] if(*word==NULL) ^~~~ main.cpp: In function 'int Prefix(Trie*, char*)': main.cpp:51:43: warning: NULL used in arithmetic [-Wpointer-arith] if(node->son[*word-'a']==NULL||*word==NULL||node->son[*word-'a']->wordcount==0) ^~~~