Compilare: user.cpp: In function ‘void create_unde()’: user.cpp:51:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<boat.size();i++) unde[boat[i]]=i; ^ user.cpp: In function ‘int main()’: user.cpp:55:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("sea.in","r",stdin); ^ user.cpp:56:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("sea.out","w",stdout); ^ user.cpp:57:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:58:75: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=n;i++) scanf("%lf%lf",&boats[i].first,&boats[i].second); ^ user.cpp:93:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%d",&light,&many); ^