Compilare: user.cpp: In function ‘void read_input()’: user.cpp:15:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.in","r",stdin); ^ user.cpp:17:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &l, &r); ^ user.cpp:19:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%u", &a[i]); ^ user.cpp: In function ‘void print_answer()’: user.cpp:72:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.out","w",stdout); ^