title: How to add an HP (health) variable to a batch game
body: <p>So, I'm making a little batch CYOA style game, and I want to make an HP variable.<br>
  I used the code : <code>set /p hp=100</code> which just shows up as 100 in the file when it's run.  </p>
  
  <p>I also can't use the code <code>%hp%</code> to make it visible when I want it to be!<br>
  Anybody got any simple ways to add a variable that can't be changed by the file's user, but can be changed if the code calls for it, and can be shown when the <code>%hp%</code> command is typed in?</p>