</pre><pre name="code" class="cpp">#include <stdio.h>

#include <malloc.h>

typedef struct BTNode

{

char data;

struct BTNode *lchild;

struct BTNode *rchild;

}BTNode;

void createTree(BTNode* *T)

{

char ch = getchar();

if(ch=='#')

{

*T=NULL;

return;

}

(*T) = (BTNode*)malloc(sizeof(BTNode));

(*T)->data = ch;

createTree(&(*T)->lchild);

createTree(&(*T)->rchild);

}

void preOrder(BTNode *T)//先序遍历

{

if(T==NULL) return;

printf("%c\t", T->data);

if(T->lchild!=NULL)

preOrder(T->lchild);

if(T->rchild != NULL)

preOrder(T->rchild);

}

void inOrder(BTNode *T)//中序遍历

{

if(T==NULL) return;

if(T->lchild!=NULL)

inOrder(T->lchild);

printf("%c\t", T->data);

if(T->rchild != NULL)

inOrder(T->rchild);

}

void postOrder(BTNode *T)//后序遍历

{

if(T==NULL) return;

if(T->lchild!=NULL)

postOrder(T->lchild);

if(T->rchild != NULL)

postOrder(T->rchild);

printf("%c\t", T->data);

}

int main(int argc, char const *argv[])

{

BTNode *T;

createTree(&T);

puts("PreOrder visit:");

preOrder(T);

putchar('\n');

puts("inOrder visit:");

inOrder(T);

putchar('\n');

puts("PostOrder visit:");

postOrder(T);

putchar('\n');

return 0;

}

/*运行结果：

ABD###C##

PreOrder visit:

A       B       D       C

inOrder visit:

D       B       A       C

PostOrder visit:

D       B       C       A

请按任意键继续. . .*/