c问题

lby1207087645

#include"stdio.h"
#include"malloc.h"

typedef struct node
{
char data;
struct node *lchild;
struct node *rchild;
}*btree;
btree creat()
{
btree t;
char ch;
scanf("%2c",&ch);
if(ch=='#')
t=NULL;
else
{
t=(btree)malloc(sizeof(struct node));
t->data=ch;
t->lchild=creat();
t->rchild=creat();

}return t;

}
void first(btree t)
{
if(t==NULL)
return ;
printf("%2c",t->data);
first(t->lchild);
first(t->rchild);
}
void main()
{
btree t=creat();
printf("请输入一个树#表示空");
first(t);

}求二叉树的先序遍历，如何输入一颗树