二叉树的创建和先序遍历

#include <stdio.h>
#include <malloc.h>
typedef struct Node
{
    char data;
    struct Node *lchild;
    struct Node *rchild;
}*btree;
btree create_tree()
{
    char element;
    printf("input element:");
    scanf(" %c",&element);
    if(element=='#')
    {
        return NULL;
    }
    btree T=(btree)malloc(sizeof(struct Node));
    T->data=element;
    printf("%c left:\n",element);
    T->lchild=create_tree();
    printf("%c right:\n",element);
    T->rchild=create_tree();
    return T;
}
void first_output(btree T)
{
    if(T==NULL)
    {
        return;
    }
    printf("%c",T->data);
    first_output(T->lchild);
    first_output(T->rchild);
}
int main() {
    btree T=create_tree();
    first_output(T);
    return 0;
}