二叉树的先序非递归遍历

#include<stdio.h>
#include<stdlib.h>
#define MAXNODE 100
typedef int status;
#define MAX 100

typedef struct Bitree
{
    struct Bitree *lchild;
    struct Bitree *rchild;
    char data;
}BiTree ,*BiTnode;

BiTree *Create( )//建立二叉树
{
    int i,j;
    BiTree *root,*s,*Q[MAX];
    char ch;
    printf("请输入要建立的树的下标和数值:");
   // getchar( );
    scanf("%d %c",&i,&ch);
    while(i!=0&&ch!='0')
    {
        s=(BiTree *)malloc(sizeof(BiTree));
        s->data=ch;printf("%d%c*",i,ch);
        s->lchild=NULL;
        s->rchild=NULL;
        Q[i]=s;
        if(i==1)
        root=s;
        else
        {
            j=i/2;
            if(i%2==0)
                Q[j]->lchild=s;
            else
                Q[j]->rchild=s;
        }
        scanf("%d %c",&i,&ch);
    }
    return root;
}

int  NRPreOrder(BiTnode bt)
{
    BiTnode stack[MAXNODE],p;
    int top;    //
    if(bt==NULL)
        return 1;
    top=-1;
    p=bt;

    while(!(p==NULL&&top==-1)){
    while(p!=NULL){//printf("*");
        printf("%c ",p->data);
        if(top<MAXNODE-1){
            top++;
            stack[top]=p;
            }
        else{
            printf("wrong\n");
            return 0;
        }
    p=p->lchild;
   }
   if(top==-1)
        return 1;
   else{
       p=stack[top];
       top--;
       p=p->rchild;
   }
  }
}


int main( )
{
    BiTnode Bt;
    Bt=Create( );
    printf("\n");
    NRPreOrder(Bt);
    return 0;
}