#include<stdio.h>
#include<stdlib.h>
typedef char datatype; //树结构体的定义
typedef struct node {
datatype data;
struct node *lchild, *rchild;
} bintree;
bintree *root;
typedef struct stack //栈的结构定义
{
bintree *data[100];
int tag[100]; //为栈中的每个元素设计标记，用于后序遍历
int top; //栈顶指针
} seqstack;
void push(seqstack *s, bintree *t) //进栈
{
s->data[s->top] = t;
s->top++;
}
bintree *pop(seqstack *s) //出栈
{
if (s->top != 0)
{
s->top--;
return (s->data[s->top]);
}
else
return NULL;
}
bintree *createbintree() //按照前序遍历顺序建立一颗给定的二叉树（递归）
{
char ch;
bintree *t;
if ((ch = getchar()) == '#')
t = NULL;
else {
t = (bintree*)malloc(sizeof(bintree));
t->data = ch;
t->lchild = createbintree();
t->rchild = createbintree();
}
return t;
}
void inorder1(bintree *t) //非递归实现二叉树的中序遍历
{
seqstack s;
s.top = 0;
while ((t) || (s.top != 0))
{
if (t)
{
push(&s, t);
t = t->lchild;
}
else
{
t = pop(&s);
printf("%c", t->data);
t = t->rchild;
}
}
}
bintree *last(bintree *t) //计算中序遍历的最后一个结点
{
if (t->rchild)
{
while (t->rchild)
{
t = t->rchild;
}
}
return t;
}
int main()
{
bintree *tree;
bintree *l;
printf("根据前序遍历输入一棵二叉树:");
tree = createbintree();
printf("\n");
printf("中序遍历输出二叉树：");
inorder1(tree);
printf("\n");
l = last(tree);
printf("中序遍历下最后一个结点：");
printf("%c",l->data);
printf("\n");
return 0;
}