Compilare: user.cpp: In function ‘int main()’: user.cpp:92:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:95:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.in", "r", stdin); ^ user.cpp:96:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.out", "w", stdout); ^ user.cpp:98:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:101:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf", &x, &y); ^