title: 11-character Social Security Number
body: <p>I have written the code but i am stuck on for the Social security number(SSN) if-condition.
  I want SSN should be 11 characters with hyphen sign, if SSN not then display error message. 
  Which convert class should I use for SSN.
  Here is my code:</p>
  
  <pre><code>double SSN;
  
  Console.Write("Enter you Social Security Number: ");
  
  SSN = Convert.ToDouble(Console.ReadLine());
  
  // Social Security Number Check
  if (SSN != 11)
  {
      Console.WriteLine("Invalid Social Security Number.");
  }
  </code></pre>