二叉树转换为双向链表

#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <deque>
#include <malloc.h>
using namespace std;
struct BinaryTreeNode
{
    int data;
      struct BinaryTreeNode * left;
      struct BinaryTreeNode * right;
};
typedef struct BinaryTreeNode * BTLink;
int CreatBinaryTree(BTLink *T)
{
    int a;
    BTLink tmp;
    scanf("%d",&a);
    if(a==0)
    {

        *T=0;
        return 1;
    }
    (*T)=(BTLink)malloc(sizeof(struct BinaryTreeNode));
    (*T)->data=a;
    //*T=tmp;
    CreatBinaryTree(&((*T)->left));
    CreatBinaryTree(&(*T)->right);
    return 0;
}
int PrintBinaryTree(BTLink T)
{

    if(T==0)
        return 1;
     printf("%d",T->data);
    PrintBinaryTree(T->left);
    PrintBinaryTree(T->right);
    return 0;
}
int BTLink2DLink(BTLink T,BTLink *s)//二叉树转换为双向链表，这里转换完成后s指向双向链表的尾部，
     //因此在主函数里面转换了下
{
    BTLink tmp=T;
    if(T==NULL)
        return 0;
    else
    {
        BTLink2DLink( T->left,s);
        (*s)->right=tmp;
        tmp->left=(*s);

        (*s)=tmp;
         BTLink2DLink( tmp->right,s );
    }
    return 0;
}

int main()
{


    BTLink BT =(BTLink)malloc(sizeof(struct BinaryTreeNode));
        BTLink head=(BTLink)malloc(sizeof(struct BinaryTreeNode));
        head->left=NULL;
        head->right=NULL;
  CreatBinaryTree(&BT);
  BTLink2DLink(BT,&head);

  while(head->left!=NULL)
  {

      head=head->left;
  }
  head=head->right;
  while(head!=NULL)
  {
      printf("%d  ",head->data);
      head=head->right;
  }
return 0;
 // PrintBinaryTree(BT);

}