Compilare: user.cpp: In constructor ‘arb::arb()’: user.cpp:28:38: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(next,NULL,sizeof(next)); ^ user.cpp: In function ‘void addUser(char*, arb*)’: user.cpp:51:14: warning: NULL used in arithmetic [-Wpointer-arith] if(*c == NULL){ ^ user.cpp: In function ‘void updateUser(char*, arb*, int)’: user.cpp:67:14: warning: NULL used in arithmetic [-Wpointer-arith] if(*c == NULL){ ^ user.cpp: In function ‘void findUser(char*, arb*)’: user.cpp:85:14: warning: NULL used in arithmetic [-Wpointer-arith] if(*c == NULL) ^