public class Stack

{

private Object[] elements;

private int top;

public Stack(int size)

{

elements = new Object[size];

top = -1; // indicate that stack is empty

}

public void push(Object o)

{

if (top + 1 == elements.length)

{

System.out.println("stack is full");

return;

}

elements[++top] = o;

}

public Object pop()

{

if (top == -1)

{

System.out.println("stack is empty");

return null;

}

Object element = elements[top--];

// elements[top + 1] = null;

return element;

}

public static void main(String[] args)

{

Stack stack = new Stack(2);

stack.push("A");

stack.push("B");

stack.push("C");

System.out.println(stack.pop());

System.out.println(stack.pop());

System.out.println(stack.pop());

}

}