二叉树的遍历
文章来源：http://blog.csdn.net/pkuyjxu/article/details/6888419
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#define OK 1
#define ERROR 0
#define OVERFLOW -2
#define MAX(a,b) (a>b?a:b)
typedef char TElemType;
typedef int Status;
//二叉树的二叉链表存储结构
typedef struct BiTNode{
TElemType data;
struct BiTNode *lchild,*rchild;
}BiTNode,*BiTree;
//先序遍历生成二叉树
Status CreatBiTree(BiTree &T){
TElemType ch,temp;
printf("输入一个元素: ");
scanf("%c",&ch);
temp=getchar(); //结束回车
if(ch==' ') T=NULL; //输入空格表示结点为空树
else{
if(!(T=(BiTree)malloc(sizeof(BiTNode)))) exit(OVERFLOW);
T->data=ch; //生成根结点
CreatBiTree(T->lchild); //构造左子树
CreatBiTree(T->rchild); //构造右子树
}
return OK;
}
//打印元素
Status PrintElem(TElemType e){
printf("%c ",e);
return OK;
}
//先序遍历二叉树
Status PreOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){
if(T){ //二叉树不为空时
if(Visit(T->data)) //访问根结点
if(PreOrderTraverse(T->lchild,Visit)) //先序遍历左子树
if(PreOrderTraverse(T->rchild,Visit)) return OK; //先序遍历右子树
return ERROR;
}
else return OK;
}
//中序遍历二叉树
Status InOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){
if(T){
if(InOrderTraverse(T->lchild,Visit))
if(Visit(T->data))
if(InOrderTraverse(T->rchild,Visit)) return OK;
else return ERROR;
}
return OK;
}
//后序遍历二叉树
Status PostOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){
if(T){
if(PostOrderTraverse(T->lchild,Visit))
if(PostOrderTraverse(T->rchild,Visit))
if(Visit(T->data)) return OK;
else return ERROR;
}
return OK;
}
//求二叉树的深度
int BiTreeDepth(BiTree T){
if(!T) return 0; //二叉树为空树时
int Dl=0,Dr=0;
if(T->lchild) Dl=BiTreeDepth(T->lchild); //求左子树深度
if(T->rchild) Dr=BiTreeDepth(T->rchild); //求右子树深度
return MAX(Dl,Dr)+1;
}
//主函数
void main()
{
BiTree T;
Status (* Visit)(TElemType);
Visit=PrintElem;
CreatBiTree(T); a
printf("\n先序遍历:");
PreOrderTraverse(T,Visit);
printf("\n中序遍历:");
InOrderTraverse(T,Visit);
printf("\n后序遍历:");
PostOrderTraverse(T,Visit);
printf("\n二叉树深度为%d",BiTreeDepth(T));
printf("\n程序结束.\n");
}
#####################################
二叉树遍历非递归算法
1.先序遍历非递归算法
#define maxsize 100
typedef struct
{
Bitree Elem[maxsize];
int top;
}SqStack;
void PreOrderUnrec(Bitree t)
{
SqStack s;
StackInit(s);
p=t;
while (p!=null || !StackEmpty(s))
{
while (p!=null) //遍历左子树
{
visite(p->data);
push(s,p);
p=p->lchild;
}//endwhile
if (!StackEmpty(s)) //通过下一次循环中的内嵌while实现右子树遍历
{
p=pop(s);
p=p->rchild;
}//endif
}//endwhile
}//PreOrderUnrec
2.中序遍历非递归算法
#define maxsize 100
typedef struct
{
Bitree Elem[maxsize];
int top;
}SqStack;
void InOrderUnrec(Bitree t)
{
SqStack s;
StackInit(s);
p=t;
while (p!=null || !StackEmpty(s))
{
while (p!=null) //遍历左子树
{
push(s,p);
p=p->lchild;
}//endwhile
if (!StackEmpty(s))
{
p=pop(s);
visite(p->data); //访问根结点
p=p->rchild; //通过下一次循环实现右子树遍历
}//endif
}//endwhile
}//InOrderUnrec
3.后序遍历非递归算法
#define maxsize 100
typedef enum{L,R} tagtype;
typedef struct
{
Bitree ptr;
tagtype tag;
}stacknode;
typedef struct
{
stacknode Elem[maxsize];
int top;
}SqStack;
void PostOrderUnrec(Bitree t)
{
SqStack s;
stacknode x;
StackInit(s);
p=t;
do
{
while (p!=null) //遍历左子树
{
x.ptr = p;
x.tag = L; //标记为左子树
push(s,x);
p=p->lchild;
}
while (!StackEmpty(s) && s.Elem[s.top].tag==R)
{
x = pop(s);
p = x.ptr;
visite(p->data); //tag为R，表示右子树访问完毕，故访问根结点
}
if (!StackEmpty(s))
{
s.Elem[s.top].tag =R; //遍历右子树
p=s.Elem[s.top].ptr->rchild;
}
}while (!StackEmpty(s));
}//PostOrderUnrec