#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#define maxsize 10
using namespace std;
typedef struct BTNode{
  char  data;
  struct BTNode *lchild;
  struct BTNode *rchild;
}BTNode;
typedef struct{
  BTNode *p;
  int lno;
}St;
void create(BTNode *&p)  //先序遍历创建二叉树
{
    char k;
    scanf("%c",&k);
    if(k=='#') p=NULL;
    else
    {
        p=(BTNode *)malloc(sizeof(BTNode));
        p->data=k;
        create(p->lchild);
        create(p->rchild);
    }
}
void preorder(BTNode *p)
{
    if(p!=NULL)
    {
    BTNode *stack[maxsize];
    BTNode *q;
    int top=-1;
    stack[++top]=p;
    while(top!=-1)
    {
        q=stack[top--];
        printf("%c ",q->data);
        if(q->rchild!=NULL)
        {
            stack[++top]=q->rchild;
        }
        if(q->lchild!=NULL)
        {
            stack[++top]=q->lchild;
        }
    }
    }
}
void postorder(BTNode *p)
{
    if(p!=NULL)
    {
        BTNode *stack1[maxsize];
        BTNode *stack2[maxsize];
        BTNode *q;
        int top1=-1,top2=-1;
        stack1[++top1]=p;
        while(top1!=-1)
        {
            q=stack1[top1--];
            stack2[++top2]=q;
            if(q->lchild!=NULL) stack1[++top1]=q->lchild;
            if(q->rchild!=NULL) stack1[++top1]=q->rchild;
        }
        while(top2!=-1)
        {
            q=stack2[top2--];
            printf("%c ",q->data);
        }
    }
}
void inorder(BTNode *p)
{
    if(p!=NULL)
    {
        BTNode *stack[maxsize];
        int top=-1;
        while(top!=-1||p!=NULL)
        {
            while(p!=NULL)  //入栈左孩子节点或有孩子节点
            {
             stack[++top]=p;
             p=p->lchild;
            }
            if(top!=-1)
            {
                p=stack[top--];
                printf("%c ",p->data);
                p=p->rchild;
            }

        }
    }
}
int main()
{
    BTNode *T;
    create(T);
    preorder(T);
    printf("\n");
    postorder(T);
    printf("\n");
    inorder(T);
    return 0;
}