Compilare: user.cpp: In function ‘double closest_points(point*, int, int, std::vector<int>&)’: user.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < band.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:55:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in", "r", stdin); ^ user.cpp:56:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.out", "w", stdout); ^ user.cpp:59:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &n); ^ user.cpp:61:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld", &p[i].x, &p[i].y); ^