Compilare: user.cpp: In function ‘int main()’: user.cpp:17:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, k, x; ^ user.cpp:17:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k, x; ^ user.cpp:17:15: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, x; ^ user.cpp:17:18: warning: unused variable ‘x’ [-Wunused-variable] int i, j, k, x; ^ user.cpp:18:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("urat.in", "r", stdin); ^ user.cpp:19:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("urat.out", "w", stdout); ^ user.cpp:21:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^