public void showMinMax()
{
   int min = _arr[0];
   int max = _arr[0];
   for (int i=1; i<_arr.length; i++)
   {
       if (_arr[i] < min)
           min = _arr[i];
       else if (_arr[i] > max)
           max = _arr[i];
   }
   System.out.println (min + "  " + max);
}