title: How to determine if a phone number (with country calling code) is equal to another (whithout country calling code)
body: <p>I am working on an application like 'Viber' for iPhone ( <a href="http://www.viber.com/" rel="nofollow">http://www.viber.com/</a> ).</p>
  
  <p>I need to use the user phone number as ID in my database.</p>
  
  <p>When the user launch the application, I need to determine which contacts use the same application.
  I can get contacts phone number with ios API.</p>
  
  <p>But this scenario is problematic when considering country calling codes ( <a href="http://en.wikipedia.org/wiki/List_of_country_calling_codes" rel="nofollow">http://en.wikipedia.org/wiki/List_of_country_calling_codes</a> ) :</p>
  
  <p>When "registering", the USER A type his phone number without country calling code.
  The USER A is in the contact list of USER B, but without the country calling code.</p>
  
  <p>For instance, in France : 
  +33 x xx xx xx xx is refering to the same phone that 0x xx xx xx xx </p>
  
  <p>Is there a simple way to resolve this problem ?</p>