Compilare: user.cpp: In function ‘void mul(long long int*, long long int*, long long int*)’: user.cpp:34:26: warning: argument to ‘sizeof’ in ‘void* memset(void*, int, size_t)’ call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess] memset(C, 0, sizeof(C)); ^ user.cpp:41:26: warning: argument to ‘sizeof’ in ‘void* memcpy(void*, const void*, size_t)’ call is the same pointer type ‘long long int*’ as the destination; expected ‘long long int’ or an explicit length [-Wsizeof-pointer-memaccess] memcpy(A, C, sizeof(C)); ^