title: C++ Simple use of regex
body: <p>I'm just trying to mess around and get familiar with using regex in c++. 
  Let's say I want the user to input the following: ###-$$-###, make #=any number between 0-9 and $=any number between 0-5. This is my idea for accomplishing this:</p>
  
  <pre><code>regex rx("[0-9][0-9][0-9]""\\-""[0-5][0-5]")
  </code></pre>
  
  <p>That's not the exact code however that's the general idea to check whether or not the user's input is a valid string of numbers. However, let's say i won't allow numbers starting with a 0 so: 099-55-999 is not acceptable. How can I check something like that and output invalid? Thanks</p>