循环链表

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

typedef struct ring
{
        char a;
        struct ring *flink;
        struct ring *slink;
} ring;


ring* sring = NULL;
ring* hring = NULL;     /* the first node */
ring* ering = NULL;     /* the end node */
void ring_pushback( ring* r, int n )
{
        static int i = 0;

        if ( i == 0 )
        {
                sring = r;
                ++i;
                hring = r;
        }
        else
        {
                sring->slink = r;
                r->flink = sring;

                sring = r;

                /* the end node */
                if ( i == n - 1 )
                {
                        sring->slink = hring;
                        hring->flink = sring;

                      ering = sring;
                }

                ++i;
        }


}


int main( void )
{
        /*ofstream fout( "beads.out" );
        ifstream fin( "beads.in" );*/

        int n, i;
        char temp;


        cin >> n;

        for ( i = 0; i < n; ++i )
        {
                cin >> temp;
                //ring* bread = (ring*)malloc( sizeof( ring ) );
                ring* bread = new ring;
                bread->a = temp;
                bread->flink = NULL;
                bread->slink = NULL;

                ring_pushback( bread, n );
        }

        ring* p = NULL;
        ring* q = NULL;

        p = hring;
        do
        {
                cout << p->a << endl;
                q = p;
                p = p->slink;

              delete q;
        }while( p != hring );



}