Compilare: user.cpp: In function ‘void read_data()’: user.cpp:22:10: warning: unused variable ‘x’ [-Wunused-variable] double x, y; ^ user.cpp:22:13: warning: unused variable ‘y’ [-Wunused-variable] double x, y; ^ user.cpp:19:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN, "r", stdin); ^ user.cpp:20:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:23:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf", &P[i].x, &P[i].y); ^