Restrict User to enter only 3 digit in UITextField and not more than 1000 ----> IOS

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

{

    if([string length]==0){

        return YES;

    }

NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];

//first, check if the new string is numeric only. If not, return NO;

NSCharacterSet *characterSet = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789,."] invertedSet];

if ([newString rangeOfCharacterFromSet:characterSet].location != NSNotFound)

{

    return NO;

}

return [newString doubleValue] < 1000;

}