inheritance_exercise

namespace Exercise_inheritance
{
    class MyStack
    {
        private readonly ArrayList Stacks = new ArrayList();

        public void Push(Object obj)
        {
            if (obj != null)
                Stacks.Add(obj);
            else
                throw new InvalidOperationException("Error : Value cannot be null or empty");
        }

        public void Clear()
        {
            Stacks.RemoveRange(0, (Stacks.Count));
        }

        public Object Pop()
        {
            var len = Stacks.Count - 1;
            if (len < 0)
                throw new InvalidOperationException("Error : Empty stack");
            else
            {
                var lasEl = Stacks[len];
                Stacks.RemoveAt(len);
                return lasEl;
            }
        }
    }
}