Java数据结构--双向链表的实现

java学习经验总结------双向链表的实现

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双向链表的建立与单链表类似，只是需要使用pre指针指向前一个结点，并且在删除添加时不仅仅考虑next

package datastructure;

public class DoubleLinkedList {//双向链表的构造使用

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		DoubleList dl = new DoubleList();
		dl.empty_add("5");
		dl.empty_add("3");
		dl.empty_add("2");
		dl.empty_add("1");
		dl.insert(2, "8");
		dl.orderprint();
		dl.reverseorderprint();
	}

}
class DoubleList{
	public Dlnode first;//头指针
	public Dlnode current;//当前结点
	private int count=0;//结点个数
	public DoubleList() {
		// TODO 自动生成的构造函数存根
		this.first=new Dlnode(null);
		current=first;
		first.next=null;
	}
	public int getCount() {//得到结点个数
		return count;
	}
	public void empty_add(String word) {//由空链表添加结点
		Dlnode newnode = new Dlnode(word);
		//current=first;
		while(current.next!=null)
			current=current.next;
		current.next=newnode;
		newnode.pre=current;
		newnode.next=null;
		current=current.next;
		this.count++;

	}
	public void orderprint() {//按照顺序遍历
		Dlnode now;

		for(now=first.next;now!=null;now=now.next)
			System.out.print(now.getWord());
		if(now==null)
			System.out.println("null");
		System.out.println("结点个数为："+this.getCount());

		/*System.out.println(current.getWord());*/
	}
	public void reverseorderprint() {//按照逆序遍历
		while(current!=null)
		{
			System.out.print(current.getWord());
			current=current.pre;
		}
		System.out.println("结点个数为："+this.getCount());
	}
	public void insert(int location,String word) {//在指定地点插入

		if(location>count)
			System.out.println("已超过结点个数，无法插入！！！");
		else {
			Dlnode now=first;
			while(true) {
				if(location==0)
					break;
				else {
					now=now.next;
					location--;
				}
			}
			Dlnode temp = new Dlnode(word);
			now.pre.next=temp;
			temp.pre=now.pre;
			now.pre=temp;
			temp.next=now;
			this.count++;

		}
	}
	/*public void delete(int location) {//删除功能留置，与添加类似
		if(location>count)
	}*/

}
class Dlnode{//链表结点
	private String word;
	public Dlnode pre;
	public Dlnode next;
	public Dlnode(String word) {
		// TODO 自动生成的构造函数存根
		this.word=word;
	}
	public String getWord() {
		return word;
	}
	public void setWord(String word) {
		this.word = word;
	}

}