Compilare: user.cpp: In function ‘void upd(trie*, char*, int)’: user.cpp:22:15: warning: NULL used in arithmetic [-Wpointer-arith] if( *s == NULL ) ^ user.cpp:24:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if( nod->next[ *s - 'a' ] == NULL ) ^ user.cpp: In function ‘void upd1(trie*, char*)’: user.cpp:42:15: warning: NULL used in arithmetic [-Wpointer-arith] if( *s == NULL ) ^