=====
Stack
=====

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Example
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Java
====

.. code-block:: java

  class Stack {
    Node top;

    Object pop() {
      if (top != null) {
        Object item = top.data;
        top = top.next;
        return item;
      }
      return null;
    }

    void push(Object item) {
      Node t = new Node(item);
      t.next = top;
      top = t;
    }

    Object peek() {
      return top.data;
    }
  }