/*二叉樹的建立*/
#include <stdio.h>
#include <malloc.h>

struct node_T
{
char data;
node_T *left;
node_T *right;
};

//遞歸調用，從鍵盤輸入字母，建立二叉樹。輸入'#'對應空樹
node_T *CreateBTree()
{
char c = getchar();
if(c=='#')
{
return NULL;
}
node_T *p = (node_T *)malloc(sizeof(node_T));
p->data = c;
p->left = CreateBTree();
p->right = CreateBTree();
return p;
}

//先序遍歷
void PreOrder(node_T *tree)
{
if(tree==NULL)
{
return;
}
printf("%c", tree->data);
PreOrder(tree->left);
PreOrder(tree->right);
}
int main()
{
node_T *root = CreateBTree();
PreOrder(root);
return 0;
}