title: get type of NSNumber
body: <p>I want to get the type of NSNumber instance.</p>
  
  <p>I found out on <a href="http://www.cocoadev.com/index.pl?NSNumber" rel="noreferrer">http://www.cocoadev.com/index.pl?NSNumber</a> this:</p>
  
  <pre>
   NSNumber *myNum = [[NSNumber alloc] initWithBool:TRUE];
  
   if ([[myNum className] isEqualToString:@"NSCFNumber"]) {
    // process NSNumber as integer
   } else if  ([[myNum className] isEqualToString:@"NSCFBoolean"]) {
    // process NSNumber as boolean
   }
  </pre>
  
  <p>Ok, but this doesn't work, the [myNum className] isn't recognized by the compiler.
  I'm compiling for iPhone.</p>