- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;
// return YES to change text
{
   if (([textField.text length] - range.length + [string length]) <= 20)
      return (YES);

   return (NO);
}

   NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] autorelease];
   [formatter setNumberStyle:NSNumberFormatterDecimalStyle];
   [formatter setLocale:[NSLocale currentLocale]];
   [formatter setGeneratesDecimalNumbers:YES];
   [formatter setAlwaysShowsDecimalSeparator:YES];
   [formatter setGroupingSize:3];
   
   NSNumber *numb = [formatter numberFromString:@"12.345,67"];
   
   double  loanAmount = [numb floatValue];

   NSLog (@"%.2f", loanAmount);