#include<stdio.h>
#include<stdlib.h>

#define MAXNUM 100
struct BiTreeNode;        /*二叉树中的结点*/
typedef struct BiTreeNode *PBiTreeNode;/*结点的指针类型*/

struct BiTreeNode
   
{
    char info;
    PBiTreeNode llink;
    PBiTreeNode rlink;
};

//typedef struct BiTree *PBiTree;
typedef struct BiTreeNode *BiTree;

struct SeqStack
 {
        BiTree s[MAXNUM];
        int t;
 };
 
 typedef struct SeqStack *PSeqStack;
 
  PSeqStack createEmptyStack_seq(void)
 {
     PSeqStack pastack;
     pastack = (PSeqStack)malloc(sizeof(struct SeqStack));
     if(pastack == NULL)
         printf("Out of space!!\n");
     else
          pastack->t = -1;
     return (pastack);
  }
  
  int isEmptyStack_seq(PSeqStack pastack)
 {
     return(pastack->t == -1);
 }
  
 void push_seq(PSeqStack pastack, PBiTreeNode p)
  {
    if(pastack->t >= MAXNUM -1)
    {
         printf("Overflow!\n");
     }
     else
      {
         pastack->t = pastack->t + 1;
         pastack->s[pastack->t] = p->s[pastack->t];
      }
}

 void pop_seq(PSeqStack pastack)
 {
      if(pastack->t == -1)
         printf("Underflow! \n");
    else
         pastack->t = pastack->t - 1;
  }
 
 int top_seq(PSeqStack pastack)
 {
    return(pastack->s[pastack->t]);
  }
PBiTree createTree(PBiTree bt)
{
    char ch;
    //printf("please input data:\n");
    scanf("%c",&ch);
   
    if(ch=='#')
    {
        bt=NULL;
    }
    else
    {
        bt=(BiTree)malloc(sizeof (BiTreeNode));
        if(!t)
            exit(0);
        bt->data=ch;
        bt->lchild=CreateTree(bt->lchild);
        bt->rchild=CreateTree(bt->rchild);
    }
    return t;
}
void PreOder(PBiTree bt)
{
    PSeqStack pastack;
    BiTreeNode *c;
    if(t==NULL)
        return;
    pastack=createEmptyStack_seq();
    push_seq( pastack, bt);
    while(!isEmptyStack_seq(pastack))
    {
        c=top_seq(pastack);
        pop_seq(pastack);
        if(c!=NULL)
        {
            printf("%c".c->data);
            push_seq( pastack, llink);
            push_seq( pastack, rlink);

        }
    }

}
int main()
{
    PBiTree bt=NULL;
    bt=createTree(bt);
    printf("Pre Order:\n");
    PreOder(bt);
    return 0;
}

谢谢版主指点，