title: what does it mean to subtract a character from a character
body: <p>i am following an example <a href="https://community.oracle.com/thread/2070706" rel="nofollow">enter link description here</a> but i have one small confusion.  What does the following line mean?</p>
  
  <pre><code>int charPos = word.charAt(0) - 'a';
  </code></pre>
  
  <p>What does it actually mean to subtract a letter from a char ?
  i am wondering if this is how you get the position of the char in the alphabet.</p>