#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#define null 0
typedef struct node
{ char data;
  node *lchild;
  node *rchild;
}* bitree;

int setup(bitree &t)
{char ch=' ';
 scanf("%c",&ch);
 if(ch==' ')t=null;
 else{
	 if(!(t=(node *)malloc(sizeof(node))))return 0;
	 t->data=ch;          //建立根節點
	 printf("%c",t->data);
	 setup(t->lchild);//建立左子樹
	 setup(t->rchild);//建立右子樹
 }
 return 1;
}

void main()
{bitree t=null;
 printf("輸入數值:");
 setup(t);
}