Compilare: user.cpp: In function ‘int main()’: user.cpp:73:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUT, "w", stdout); ^ user.cpp: In function ‘void readData()’: user.cpp:20:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN, "r", stdin); ^ user.cpp:21:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:22:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i = 0; i < N; ++i) scanf(" %d", &v[i]); ^