9. 13. 7. Demonstrate the generic Stack class.

import java.util.EmptyStackException;
import java.util.Stack;


public class StackDemo {
	static void showpush(Stack<Integer> st,int a){
		st.push(a);
		System.out.println("push(" + a +")");
		System.out.println("Stack:" + st	);
	}
	
	static void showpop(Stack<Integer> st){
		System.out.println("pop -> ");
		Integer a = st.pop();
		System.out.println(a);
		System.out.println("Stack:" + st);
	}

	public static void main(String[] args) {
		Stack<Integer> st = new Stack<Integer>();
		System.out.println("Stack:" + st);
		
		showpush(st,42);
		showpush(st, 66);
	    showpush(st, 99);
	    showpop(st);
	    showpop(st);
	    showpop(st);
	    
	    try {
	        showpop(st);
	      } catch (EmptyStackException e) {
	        System.out.println("empty stack");
	      }
	    /**
	     * Stack:[]
	     * push(42)
	     * Stack:[42]
	     * push(66)
	     * Stack:[42, 66]
	     * push(99)
	     * Stack:[42, 66, 99]
	     * pop -> 
	     * 99
	     * Stack:[42, 66]
	     * pop -> 
	     * 66
	     * Stack:[42]
	     * pop -> 
	     * 42
	     * Stack:[]
	     * pop -> 
	     * empty stack
	     */
	}

}