[Valmont]

  
#include <fstream>
#include <iostream>

int main(int argc, char *argv[])
{
  ofstream createOpenTest("ABCDEFGHIJ LKMNO PQRST UVWXY ZABCD EFGHI.state");
  int a(0);
  createOpenTest<<5;
  createOpenTest.close();
  
  ifstream readOpenTest("ABCDEFGHIJ LKMNO PQRST UVWXY ZABCD EFGHI.state");
  readOpenTest>>a;
  readOpenTest.close();
  
  cout<<a<<endl;

  return 0;
}
 

If you want to know what it does then read a basic tutorial on file streams.