title: C# Replacing part of string by start and end position
body: <p>I have a string and I want to replace a part of it.
  The tricky part is that that I can't use Regex.replace, because I only know the start and end positions of the data in the string.
  For example, if the string looks like this:</p>
  
  <pre><code>I love cats, some more stuff here, we dont know how much more
  </code></pre>
  
  <p>And I have <code>start=8</code> and <code>end=11</code>. And I want to replace that part to whatever I need to. This time lets say <code>dogs</code> so the new string will look like:</p>
  
  <pre><code>I love dogs, some more stuff here, we dont know how much more
  </code></pre>
  
  <p>How I could do that?</p>