题目6:从尾到头打印链表

 * class ListNode {
 *	String value;
 *  ListNode next;
 *
 *    public ListNode(String value, ListNode next) {
 *      this.value = value;
 *      this.next = next;
 *    }
 *   
 *    public ListNode(String value) {
 *		this.value = value;
 *	  }
 *  }
 */
public class  {
	public static void main(String[] args) {
		ListNode head = new ListNode("a");
		ListNode node1 = new ListNode("b");
		ListNode node2 = new ListNode("c");
		ListNode node3 = new ListNode("d");
		// 初始化链表
		head.next = node1;
		node1.next = node2;
		node2.next = node3;
		PrintReversingly_Iteratively(head);
	}

	public static void PrintReversingly_Iteratively(ListNode node) {
		Stack<ListNode> nodeStack = new Stack<>();
		while (node != null) {
			nodeStack.push(node);
			node = node.next;
		}
		while (!nodeStack.isEmpty()) {
			ListNode tempNode = nodeStack.pop();
			System.out.println(tempNode.value);// 打印元素
		}
	}
}