【线性表5】线性表的链式实现：循环单链表

#include<iostream>
#include<cstdlib>
#include<stdexcept>

using namespace std;

struct ListNode
{
    int element;
    ListNode* next;
    
    ListNode(int e=0,ListNode* nxt=0):element(e),next(nxt)
    {
    }
    
};

class CircleList
{
private:
    
    
    ListNode headNode;    //头结点 
    ListNode* p_rear;     //尾结点指针 
    int size;             //表长度 

public:
    CircleList():headNode(0,0),p_rear(0),size(0)
    {
        p_rear = &headNode;        //尾结点指针初始化时也保存头结点的地址 
        headNode.next = &headNode; //形成环 
    }
    
    ~CircleList()
    {
        ListNode * p = headNode.next;
        
        ListNode *t ;
        while( p!= &headNode  )
        {
            t = p;
            p = p->next;
            delete t;    
        }
    }
    
    
    void append(int e)
    {
        ListNode *new_node = new ListNode(e,&headNode);   //新结点创建 ，新结点的next指向头结点。 
        
        p_rear->next = new_node;
        p_rear = new_node;
        size++;
        
    } 
    
    
    void show()const
    {
        ListNode *p = headNode.next;
        cout<<‘[‘;
        while(p!=&headNode)
        {
            if(p!=headNode.next) 
                cout<<‘,‘;
            cout<<p->element;
            p = p->next;
        }
        cout<<‘]‘;
    } 
};



int main()
{
    
    CircleList clist;
    
    clist.append(12);
    clist.append(13);
    clist.append(14);
    clist.append(15);
    clist.append(16);
    clist.show();


}