File I/O, or input/output, is a fairly technical subject. Fortunately for us, as it is such a common requirement in programming, there is a library that handles all the complexity for us. As with concatenating strings for our HUD, it is the Standard Library that provides the necessary functionality through fstream.

First, we include fstream in the same way we included sstream:

#include "stdafx.h" 
#include <sstream> 
#include <fstream> 
#include <SFML/Graphics.hpp> 
#include "ZombieArena.h" 
#include "Player.h" 
#include "TextureHolder.h" 
#include "Bullet.h" 
#include "Pickup.h" 
 
using namespace sf; 

Now, add a new folder in the ZombieArena/ZombieArena folder called gamedata. Next, right-click in this folder and create a new file called scores.txt. It is in this file that we will save the player's high-score. You could open the file and add a score to it. If you do, make sure it is...