title: custom sort method in Delphi to sort list of strings
body: <p>I am trying to sort a list of files (they are stored as list of strings) in Delphi whose names look like below</p>
  
  <pre><code>a_1.xml
  a_20.xml
  a_10.xml
  a_2.XML
  </code></pre>
  
  <p>when i use quick sort to <code>sort</code> the file names, it sorts the file names as below </p>
  
  <pre><code>a_1.xml
  a_10.xml
  a_2.xml
  a_20.XML
  </code></pre>
  
  <p>But, I want the file names to be sorted in the below fashion</p>
  
  <pre><code>a_1.xml
  a_2.xml
  a_10.xml
  a_20.XML
  </code></pre>
  
  <p>Any help will be greatly appreciated.</p>