数据结构 二叉树 索引链表 及其索引话 输出

#include <iostream>
#include <string.h>
using namespace std;
class tree
{
public:
char c;
tree *lchild,*rchild;
int ltag,rtag;
};
char c;
tree *pre;
int main()
{
void build(tree * &p);
void inthread(tree* p,tree* &list);
void Inorder(tree* p,tree* list);
tree *head,*list;
build(head);
inthread(head,list);
Inorder(head,list);
cout<<endl;
return 0;
}
void build(tree* &p)
{
cin>>c;
if(c=='$')
{
p=NULL;
}else
{
p=new(tree);
p->c=c;
p->ltag=0;
p->rtag=0;
build(p->lchild);
build(p->rchild);
}
}
void inorderthread(tree *p)
{
if(p)
{
inorderthread(p->lchild);
if(!p->lchild)
{
p->ltag=1; p->lchild=pre;
}
if(!pre->rchild)
{
pre->rtag=1;
pre->rchild=p;
}
pre=p;
inorderthread(p->rchild);
}
}
void inthread(tree* p,tree* &list)
{
list=new(tree);
list->ltag=0; list->rtag=1;
list->rchild=list;
if(p==NULL)
{
list->lchild=list;
}else
{
list->lchild=p;
pre=list;
inorderthread(p);
pre->rchild=list; pre->rtag=1;
list->rchild=pre;
}
}
void Inorder(tree* p,tree *list)
{
while(p!=list)
{
while(p->ltag==0)
{
p=p->lchild;
}
cout<<p->c;
while(p->rtag&&p->rchild!=list)
{
p=p->rchild;
cout<<p->c;
}
p=p->rchild;
}
}