linklist.java

对已建立的单链表实现插人、删除、查找等基本操作

//import java.awt.*;
//import java.lang.*;
class LinkList implements List{
	private Node head;
	private int length=0;
	
	public LinkList(){
		head=new Node(null);
	}
	
	public void clear() //置空表
	{
		Node p=head;
		p.next=null;
		length=0;
	}
	
	public int getLength()//求表长
	{
		return length;
	}
	
	public Object getEntry(int i) //取出第i个元素
	{
		if(length==0||i<1||i>length)
		return null;
		else
		{
			Node p=head;
			for(int count=0;count<i;count++)
			p=p.next;
			return p.data;
		}	
	}
	
	public boolean isEmpty() //判表空运算
	{
		boolean isEmpty=false;
		Node p=head;
		if(p.next==null||length==0)
		isEmpty=true;
		return isEmpty;
	}
	
	public boolean add(int i, Object newEntry)//将数据元素插入线性表中第i个元素之前
	{
		boolean isSuccessful=true;
		int count=0;
		Node p=head;
		while(p!=null&&count<i-1){
			p=p.next;
			count++;
		}
		if(p==null||count>i-1){
			isSuccessful=false;
			System.out.println("It is !");
			}
		else{
			Node s=new Node(newEntry);
			s.next=p.next;
			p.next=s;
			length++;
		}
		return isSuccessful;
	}
	
	public Object remove(int i) //删除第i个元素,并将被删除的元素返回
	{
		Object s=null;
		int count=0;
		Node p=head;
		while(p.next!=null&&count<i-1)
		{
			p=p.next;
			count++;
		}
		if(p==null||count>i-1)
			System.out.println("sha chu wei zhi fei fa!");
		else
		{
			s=p.next.data;
			p.next=p.next.next;
			length--;	
		}	
		return s;
	}
	
	public boolean add(Object newEntry)   //将数据元素插入线性表的表头
	{
		Node p=head;
		Node s=new Node(newEntry);
		s.next=p.next;
		p.next=s;
		length++;
		return true;
		
	}
	public boolean reverse()
	{
		Node p=head.next;
		head.next=null;
		Node q;
		for(int count=0;count<length;count++){
			q=p;	
			p=p.next;
        	q.next=head.next;
			head.next=q;
		}
		return true;					
	}
	public void display()
	{
		Node p=head;
		for(int i=0;i<length;i++)
		{
			p=p.next;
			System.out.print(p.data+"  ");
		}
		System.out.println("");
	}
}