testlink.java

JAVA 入门小程序

class Node
{
	private Object value;
	private Node next ;
	Node(Object value)
	{
		this.value = value;
		next = null;
	}
	Node getNext()
	{
		return this.next;
	}
	void setNext(Node next)
	{
		this.next = next;
	}
	Object getValue()
	{
		return this.value;
	}
	
}
class Link
{
	private Node first;
	private Node last;
	private int i =0 ;
	void add(Object o)
	{
		if(first==null)
		{
			last = first = new Node(o);
		}
		else
		{
			
				Node n = new Node(o);
				last.setNext(n);
				last = n;
			
		}
		i++;
	}
	void addFirst(Object o)
	{
		Node n = new Node(o);
		n.setNext(first);
		first = n;
		i++;	
	}
	void addLast(Object o)
	{
		add(o);	
		
	}
	Object getFirst()
	{
		return first.getValue();
	}
	
	Object getLast()
	{
		return last.getValue();
	}
	void removeFirst()
	{
		first = first.getNext();
		i--;	
	}
	void removeLast()
	{
		Node n = first;
		while(n.getNext()!=last)
		{
			n = n.getNext();
		}
		last = n;
		i--;	
	}
	int getSize()
	{
		return this.i;	
	}
	
}
public class TestLink
{
	public static void main(String args[])
	{
		Link l = new Link();
		l.add("a");
		l.add("b");
		l.addFirst("c");
		l.addLast("d");
		
		System.out.println(l.getFirst());
		System.out.println(l.getLast());
		System.out.println(l.getSize());
		l.removeFirst();
		l.removeLast();
		System.out.println(l.getFirst());
		System.out.println(l.getLast());
		System.out.println(l.getSize());
	}
}