Compilare: user.cpp: In function ‘int main()’: user.cpp:61:12: warning: unused variable ‘i’ [-Wunused-variable] int n, i; ^ user.cpp:59:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "dirichlet.in", "r", stdin ); ^ user.cpp:60:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "dirichlet.out", "w", stdout ); ^ user.cpp:62:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d", &n ); ^