C++双向链表的应用

#include <iostream>#include <cstdio>using namespace std;struct cha{    cha *prior;    char ch;    cha *next;};int main(){    cha *a,*p;    p=new cha;    cin>>p->ch;    p->next=p->prior=NULL;    a=p;    p=new cha;    while((a->ch=getchar())!='\n')    {        p->next=a;        a->prior=p;        p->prior=NULL;        a=p;        p=new cha;    }    while((a=a->next)!=NULL)    {        cout<<a->ch<<' ';    }    return 0;}