package clink;
//循环单链表
public class TestClink {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
    Clink t1 = new Clink();
    for(int i = 0;i<9;i++){
        t1.insertHead(i);
        
    }
    
    t1.show();
    int len=t1.getlength();
    System.out.println(len);
    System.out.println("---");
    t1.insertTail(5);
    t1.insertTail(5);
    t1.show();
    System.out.println("---");
    t1.delete(5);
    t1.show();
    }

}
class Clink{
    class Entry{
        int data;
        Entry next;
        public Entry(){
            this.data=-1;
            this.next=null;
        }
        public Entry(int data){
            this.data=data;
            this.next=null;
        }
    }
    private Entry head=null;
    public Clink(){
        this.head=new Entry();
        this.head.next=this.head;
    }
    //头插法
    public void insertHead(int val){
        Entry entry=new Entry(val);
        entry.next=this.head.next;
        this.head.next=entry;
    }
    //尾插法
    public void insertTail(int val){
        Entry cur=this.head;//定义一个节点用来寻找链表的尾结点
        while(cur.next!=this.head){
            cur=cur.next;
        }
        Entry entry=new Entry(val);//定义要插入的节点
        entry.next=cur.next;
        cur.next=entry;
        
    }
    public boolean isEmpty(){
        Entry cur=this.head;
        if(cur.next!=this.head){
            return false;
        }
        return true;
    }
     删除值为5的所有节点
    public boolean delete(int val){//此时删除5
        
        Entry prev=this.head;
        Entry cur=this.head.next;
        if(isEmpty()){
            return false;
        }
        while(cur!=this.head){
        
            if(cur.data==val){
            prev.next=cur.next;
            cur=prev.next;
            }else{
                prev=cur;
                cur=cur.next;
            }
            }return true;
    }
    
    /*public void delete(int val){
            
            Entry prev=this.head;
            Entry cur=this.head.next;
            while(cur!=this.head){
             if(cur.data==val){
                prev.next=cur.next;
                cur=prev.next;
                
                }else{
                    prev=cur;
                    cur=cur.next;
                
                }
            }
              
    }*/
    public int getlength(){
        Entry cur=this.head;
        int len=0;
        while(cur.next!=head){
            len++;
            cur=cur.next;
        }
        return len;
    }
    public void show(){
        Entry cur=this.head.next;
        while(cur!=this.head){
            System.out.println(cur.data+"data");
            cur=cur.next;
        }
        System.out.println();
    }
    
}