Java用链表实现栈和队列

    用链表实现了栈的基本操作：入栈、出栈、查看栈顶数据以及判断栈是否有数据

/**
 * 用链表实现栈
 * @author Administrator
 *
 * @param <E>
 */


public class MyStackLink<E>
{
	//定义一个初始长度为0的数组来缓存数据
		Node head = null;
		int length = 0;//结点个数
		
		
		//将数据压入栈中
		public void push(E e)
		{
			//创建结点
			Node n = new Node(e);
			n.next=head;
			head=n;
			length++;
			
		}
		//查看栈顶的数据
		public E get()
		{
			
//			return head == null?null:head.e;
			return head.e;
		}
		
		//出栈
		public E poll()
		{ 
			if(head==null)
			{
				return null;
			}
			Node n=head;
			head = n.next;
			n.next=null;
			length--;
			return n.e;
		}
		
		//判断栈是否为空
		public boolean isEmpty()
		{
			return length == 0;
		}
		private class Node
		{
			E e;
			Node next;
			public Node(E e)
			{
				this.e = e;
			}
		}
}

     因为代码和功能基本上差不多就在这里一起用链表实现了队列

/**
 * 用链表实现队列
 * @author Administrator
 *
 * @param <E>
 */


public class Queue<E>
{

			Node head = null;
			private Node last = null;
			int length = 0;//结点个数
			
			//将数据放入队列中
			public void push(E e)
			{
				//创建结点
				Node n = new Node(e);
				if(head==null)
				{
					head = n;
				}else
				{
					last.next = n;
				}
				last = n;
				length++;
				
			}
			//查看队列的数据
			public E get()
			{
				
				return head == null?null:head.e;
			}
			
			//去队列的首数据
			public E poll()
			{ 
				if(head==null)
				{
					return null;
				}
				Node n=head;
				head = n.next;
				n.next=null;
				length--;
				return n.e;

			}
			
			//判断队列是否为空
			public boolean isEmpty()
			{
				return length == 0;
			}
			private class Node
			{
				E e;
				Node next;
				public Node(E e)
				{
					this.e = e;
				}
			}
}