java实现链表指定值得删除，查找第二部分代码

  1 package com.liu.Link;
  2 
  3 public class LinkList1 {
  4     private Link first;
  5     public LinkList1()
  6     {
  7         first = null;
  8     }
  9     
 10     public void insertFirst(int id,double dd)
 11     {
 12         Link newLink = new Link(id,dd);
 13         newLink.next = first;
 14         first = newLink;
 15     }
 16     
 17     public Link find(int key)
 18     {
 19         Link current = first;
 20         while(current.iData!=key)
 21         {
 22             if(current.next == null)
 23                 return null;
 24             else
 25                 current = current.next;
 26         }
 27         return current;
 28     }
 29     
 30     public Link delete(int key)
 31     {
 32         Link current = first;
 33         Link previous = first;
 34         while(current.iData != key)
 35         {
 36             if(current.next == null)
 37                 return null;
 38             else
 39             {
 40                 previous = current;
 41                 current = current.next;
 42             }
 43         }
 44         //情况1，删除的数字就是first指针指向的位置
 45         if(current == first)
 46         {
 47             first = first.next;
 48         }
 49         //情况2，删除的数字是中间位置
 50         else
 51         {
 52             previous.next = current.next;
 53         }
 54         //current就是previous.next
 55         return current;
 56     }
 57     
 58     public void displayList()
 59     {
 60         System.out.print("List (first-->last):");
 61         Link current = first;
 62         while(current != null)
 63         {
 64             current.displayLink();
 65             current = current.next;
 66         }
 67         System.out.println("");
 68     }
 69 }
 70 
 71 //链表数据类
 72 class Link
 73 {
 74     public int iData;
 75     public double dData;
 76     public Link next;
 77     
 78     public Link(int id,double dd)
 79     {
 80         iData = id;
 81         dData = dd;
 82     }
 83     
 84     public void displayLink()
 85     {
 86         System.out.print("{"+ iData +", "+ dData +"}");
 87     }
 88     
 89 }
 90 
 91 class LinkListApp
 92 {
 93     public static void main(String args[])
 94     {
 95         LinkList1 theList = new LinkList1();
 96         theList.insertFirst(22, 2.99);
 97         theList.insertFirst(44, 4.99);
 98         theList.insertFirst(66, 6.99);
 99         theList.insertFirst(88, 8.99);
100         theList.insertFirst(33, 3.99);
101         
102         theList.displayList();
103         
104         Link f = theList.find(44);
105         if(f!=null)
106             System.out.println("Fount link with key "+f.iData);
107         else
108             System.out.println("can‘t find link");
109         
110         Link d = theList.delete(66);
111         if( d != null )
112              System.out.println("Deleted link with key " + d.iData);
113           else
114              System.out.println("Can‘t delete link");
115         
116         theList.displayList();
117     }
118 }