How to search and replace exact matching strings only
<p>I need to search in a string and replace a certain string</p>

<blockquote>
  <p>Ex: Search String "Add Additional String to text box".
      Replace "Add" with "Insert"</p>
  
  <p>Output expected = "Insert Additional String to text box"</p>
</blockquote>

<p>If you use string s="Add Additional String to text box".replace("Add","Insert");</p>

<blockquote>
  <p>Output result = "Insert Insertitional String to text box"</p>
</blockquote>

<p>Have anyone got ideas to get this working to give the expected output?</p>

<p>Thank you!</p>
