title: Regular Expression for SSN
body: <p>I have a method in C# that says FormatSSN that takes a SSN in a string format and replaces the dashes. I mean I am expecting the SSN to be in XXX-XX-XXXX format. I want to write a regular expression that makes sure that the SSN is in the format I have mentioned.</p>
  
  <p>Can anyone help me construct a regular expression??</p>