Compilare: user.cpp: In function ‘long long int catalan(int, int)’: user.cpp:31:17: warning: unused variable ‘ok’ [-Wunused-variable] int ok = 1; ^ user.cpp: In function ‘int main()’: user.cpp:65:12: warning: unused variable ‘i’ [-Wunused-variable] int n, i; ^ user.cpp:63:40: 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:64:42: 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:66:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^