title: error after calling TimeIntervalSinceNow on an NSDate?
body: <p>I'm using the following method to determine the number of days between two NSDate's :</p>
  
  <pre><code>- (int)daysBetweenDate:(NSDate *)start andDate:(NSDate *)end {
  
      NSTimeInterval lastDiff = [start timeIntervalSinceNow];
      NSTimeInterval todaysDiff = [end timeIntervalSinceNow];
      NSTimeInterval dateDiff = lastDiff - todaysDiff;
  
      double numOfDays = dateDiff/86400; //86400 seconds in a day
  
      return (int)(numOfDays + 0.5);
  
  }
  </code></pre>
  
  <p>And I'm calling it like this:</p>
  
  <pre><code>int numOfDays = [self daysBetweenDate:lastResetDay andDate:[dict objectForKey:@"nsDate"]];
  </code></pre>
  
  <p>Both values I'm passing in are NSDate's</p>
  
  <p>The above is called while enumerating through an NSMutableArray.</p>
  
  <p>And after running this I'm getting the following error:</p>
  
  <p>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UITableView timeIntervalSinceNow]: unrecognized selector sent to instance 0x6818600'</p>