title: Can Regex be used for this particular string manipulation?
body: <p>I need to replace character (say) <strong>x</strong> with character (say) <strong>P</strong> in a string, but only if it is contained in a quoted substring.
  An example makes it clearer:</p>
  
  <pre><code>axbx'cxdxe'fxgh'ixj'k  -&gt; axbx'cPdPe'fxgh'iPj'k
  </code></pre>
  
  <p>Let's assume, for the sake of simplicity, that quotes always come in pairs. </p>
  
  <p>The obvious way is to just process the string one character at a time (a simple state machine approach);<br>
  however, I'm wondering if regular expressions can be used to do all the processing in one go.</p>
  
  <p>My target language is C#, but I guess my question pertains to any language having builtin or library support for regular expressions.</p>