Compilare: user.cpp: In function ‘void solve_hull()’: user.cpp:66:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<nothull.size();i++) printf("%d ",nothull[i]); ^ user.cpp: In function ‘int main()’: user.cpp:73:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("testament.in","r",stdin); ^ user.cpp:74:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("testament.out","w",stdout); ^ user.cpp:75:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:77:91: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=k;i++) scanf("%d%d",&points[i].first,&points[i].second),points[i].pos=i; ^