Compilare: user.cpp: In function ‘void Query()’: user.cpp:50:10: warning: unused variable ‘v’ [-Wunused-variable] char v; ^ user.cpp: In function ‘void addWord(Trie*, char*)’: user.cpp:77:27: warning: NULL used in arithmetic [-Wpointer-arith] if ( tolower(s[0]) == NULL ) ^ user.cpp: In function ‘void increaseRelevance(Trie*, char*)’: user.cpp:98:27: warning: NULL used in arithmetic [-Wpointer-arith] if ( tolower(s[0]) == NULL ) ^