This function will always work on the first call and will never work on immediate 
succesive tries.

void read(){

   char* instr;
   fstream fs;
   fs.open(filename,ios::in);
        
   while(!fs.eof()){

        fs.get(instr,10);
        cout << "Data " << instr << endl;
   }
   fs.flush();
   fs.close();   
}

If the char* is a parameter it works fine every time.

void read(char* instr){


   fstream fs;
   fs.open(filename,ios::in);
        
   while(!fs.eof()){

        fs.get(instr,10);
        cout << "Data " << instr << endl;
   }
   fs.flush();
   fs.close();   
}