Re: How to improve my question in stackoverflow?

[IL Ka <kazakevichilya@gmail.com>]

Moreover, the included things are files, and by convention they
have a suffix ".h", for "header". I'd expect the above to look
rather like

  #include <set.h>
  #include <map.h>
  #include <string.h>
  #include <map.h>
  #include <fstream.h>
  #include <algorithm.h>

This is true for C, but not for C++.

With C++ headers could be files or not, so you shouldn't add ".h".

The problem is probably "set" written as "Set": C++ is case sensitive.