（1）建立含有n个结点的二叉树链表； （2）按照先序、中序、后序遍历的顺序依次输出二叉树的各个结点。

Question

请用C或C++语言编写，谢谢~

Answer 1

#include <stdio.h>
#include <stdlib.h>

typedef char Elem;

typedef struct Node
{
Elem data;
struct Node *pLchild;
struct Node *pRchild;
}BTreeNode, *BTree;

BTree CreateBTree(BTree T)//创建二叉树
{
Elem x;

scanf("%c", &x);

if ('0' == x)
{
T = NULL;
}
else
{
T = (BTree) malloc (sizeof(BTreeNode));
T->data = x;

T->pLchild = CreateBTree(T->pLchild);
T->pRchild = CreateBTree(T->pRchild);
}

return T;
}

void PostTraverseBTree(BTree T)//后序
{
if (NULL != T)
{
PostTraverseBTree(T->pLchild);
PostTraverseBTree(T->pRchild);
printf("%c ", T->data);
}
}

void InTraverseBTree(BTree T)//中序
{
if (NULL != T)
{
InTraverseBTree(T->pLchild);
printf("%c ", T->data);
InTraverseBTree(T->pRchild);
}
}

void PreTraverseBTree(BTree T)//前序
{
if (NULL != T)
{
printf("%c ", T->data);
PreTraverseBTree(T->pLchild);
PreTraverseBTree(T->pRchild);
}
}

int main(void)
{
BTree T = NULL;

printf("请输入二叉树元素:\n");
T = CreateBTree(T);
printf("\n\n");

printf("先序遍历:\n");
PreTraverseBTree(T);
printf("\n\n");

printf("中序遍历:\n");
InTraverseBTree(T);
printf("\n\n");

printf("后序遍历:\n");
PostTraverseBTree(T);
printf("\n\n");
}

如下面的二叉树：（无左右孩子输入0）
A
B C
D E F G

则输入：ABCD00E00F00G00回车