Reverse of string in objective C

- (NSString*)reverseString:(NSString*)string

{

   NSMutableString *reversedString;

   int length     = [string length];

   reversedString = [NSMutableString stringWithCapacity:length];

   while (length--) 

   {

      [reversedString appendFormat:@"%C", [string   characterAtIndex:length]];

   }

  return reversedString;

}