import java.util.*;

public class IterStack 
{
    protected int data[];
    protected int top;
    
    public IterStack(int size)
    {
        data = new int[size];
        top = 0;
    }
    

    public void push(int elem)
    {
        data[top++] = elem;
    }
    public int pop()
    {
        return data[--top]; 
    }
    
    public Iterator<Integer> iterator()
    {
        return new StackIterator();
    }
    
    /// This is an inner class, so it can access any / all data memebrs
    /// of the containing class    
    private class StackIterator implements Iterator<Integer>
    {
        private int position;

        public StackIterator()
        {
            position = 0;
        }

        public boolean hasNext()
        {
            return position < top;
        }
        public Integer next()
        {
            return new Integer(data[position++]);
        }
        public void remove()
        {
            throw new UnsupportedOperationException();
        }        
    }
    

    public static void main(String args[])
    {
        IterStack t = new IterStack(30);
        
        t.push(3);
        t.push(4);
        t.push(5);
        
        Iterator<Integer> it = t.iterator();
        while (it.hasNext())
            System.out.println(it.next());
    }
}