Compilare: user.cpp: In function ‘int main()’: user.cpp:42:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < E.size(); ++ i) { ^ user.cpp:50:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; index + 1 < F.size() && F[index + 1].second < i; ++ index) ^ user.cpp: In function ‘void read_in()’: user.cpp:15:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", & N, & L); ^ user.cpp:17:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", C + i); ^ user.cpp:19:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", & lo, & hi); ^ user.cpp: In function ‘int main()’: user.cpp:39:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(iname, "r", stdin); ^ user.cpp:59:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(oname, "w", stdout); ^