title: How can I change the first two characters of a string to "01" with C#?
body: <p>I have strings like this:</p>
  
  <pre><code>var abc = "00345667";
  var def = "002776766";
  </code></pre>
  
  <p>The first two characters are always "<code>00</code>".  How can I change these to "<code>01</code>" ?</p>