title: Credit Card Verification Regular Expression
body: <p>I am having some issues creating a regex for a credit card number verifier in Visual C#.
  The numbers for the card need to be separated by dashes(-), the first number must be 1-9, and the second set of numbers must be 1-3. So an example would be 2204-1232-9746-5558, or 1111-1111-1111-1111.</p>
  
  <p>here is what I have so far:</p>
  
  <pre><code>    Regex card = new Regex(@"^[1-9][0-9]{2}-[1-3]{3}-[0-9]{3}-[0-9]{3}$");
          string myCard = txtCard.Text;
          Match m  = card.Match(myCard);
  
          if(m.Success)
          {
              MessageBox.Show("The card number entered is vaild");
          }
          else
          {
              MessageBox.Show("The card number entered is an invaild card number...");
          }
  
          txtCard.Clear();
          txtCard.Focus();
  </code></pre>
  
  <p>Every card number I try gives me the same result, the number is invalid.
  Can anyone steer me in the right direction?
  Much thanks!</p>