Compilare: main.cpp: In function 'int main()': main.cpp:18:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("iopds.in", "r", stdin); ^ main.cpp:19:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("iopds.out", "w", stdout); ^ main.cpp:23:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%lf%lf%lf%d", &a, &b, &c, &n); ^ main.cpp:27:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%lf", &v[i]); ^