#include <iostream>
#include <fstream>

int main(){
  int a;
  std::filebuf out;
  out.open("pippo",std::ios::out);
  std::ostream output(&out);

  output <<12<<std::endl;
  out.close();

  std::filebuf in;
  in.open("pippo",std::ios::in);
  std::istream input(&in);
  //  std::cin>>a;
  input>> a;

  in.close();
  std::cout <<"il tuo numero era "<<a<<std::endl;
}