Compilare: main.cpp: In function 'int main(int, const char**)': main.cpp:252:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<dr.size();++i) ~^~~~~~~~~~ main.cpp:267:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<st.size();++i) ~^~~~~~~~~~ main.cpp:223:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.in","r",stdin); ^ main.cpp:224:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.out","w",stdout); ^ main.cpp:227:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:231:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf%lf",&x,&y,&z); ^