//  Data Structures with Java by John R. Hubbard
//  Copyright McGraw-Hill, 2001
//  Problem 6.15 on page 121
//  Testing another penultimate(Stack) method

import java.util.Stack;

public class Pr0615
{ public static void main(String[] args)
  { Stack kids = new Stack();
    kids.push("Sara");
    kids.push("John");
    kids.push("Andy");
    kids.push("Mike");
    System.out.println(kids);
    System.out.println(penultimate(kids));
    System.out.println(kids);
  }
  
  private static Object penultimate(Stack stack)
  { if (stack.size()<2) return null;
    return stack.elementAt(stack.size()-2);
  }
}