Compilare: user.cpp: In function ‘int main()’: user.cpp:14:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d", &n); n > 0 ; --n) ^ user.cpp:16:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &op, &x); ^