Compilare: user.cpp: In function ‘int main()’: user.cpp:205:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &n, &m); ^ user.cpp:211:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d ", &op, &a, &b, &c); ^