class Client {
    public static void main (String[]  args) {
	Stack stack = new ArrayStack();
	for (int i = 0; i<4; i++) stack.push(new Integer(i));
	assert stack.toString().equals("stack[0, 1, 2, 3]");
	int top = ((Integer)stack.pop()).intValue();
	assert top==3 && stack.toString().equals("stack[0, 1, 2]");
	Stack reverse = Stacks.reverse(stack);
	assert stack.empty();
	assert reverse.toString().equals("stack[2, 1, 0]");
    }
}