/in/foo.cc: In function 'int main()':
/in/foo.cc:32:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
/in/foo.cc:35:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&data[i].h,&data[i].v);
                                      ^