title: Batch file Array creation/modification
body: <p>so i am trying to make an array using batch, i know, primitive, but i'm learning code from the ground up, so batch is something i'd love very much to learn before i jump to something else, anyways, i know i can create an array using this syntax:</p>
  
  <p><code>@echo off 
   set a[0] = 1
   set a[1] = 2
   set a[2] = 3
   set a[3] = my input variable here</code></p>
  
  <p>My question is, how can i add a new line to the array or modify an existing one using user input ?</p>
  
  <p>I mean that i'd like to use a user input variable as a new line or modify an existing line on the array !</p>