队列和堆栈实现二叉树的遍历

#include<iostream>
#include <limits>
#include <ctime>
using namespace std;

typedef struct node{//二叉树节点
int value;
node *left;
node *right;
}node,*pnode;

typedef struct list{//队列的基本结构
pnode pn;
list *next;
}list,*plist;

typedef struct queue{//层次遍历时存储节点
list *head;
list *tail;
}queue,*pqueue;

typedef struct stack{//栈-模拟递归遍历
list *top;
}stack,*pstack;

void build_binary_tree(pnode &pn,int depth,int maxDep)//创建一个二叉树
{
if(depth<maxDep){
//创建根节点
pn=new node;
pn->value=rand()%101-50;
pn->left=NULL;
pn->right=NULL;
cout<<pn->value<<"\t";

build_binary_tree(pn->left,depth+1,maxDep);
build_binary_tree(pn->right,depth+1,maxDep);
}
}

void travel_recursive_binary_tree(pnode pn)//递归遍历二叉树
{
if(pn!=NULL){
cout<<pn->value<<"\t";
travel_recursive_binary_tree(pn->left);
travel_recursive_binary_tree(pn->right);
}
}

void travel_stack_binary_tree(pnode pn)//利用堆栈模拟递归遍历
{
if(pn!=NULL){
pstack ps=new stack;//栈
plist pl;//链表
ps->top=NULL;
while(pn||ps->top){
if(pn){
cout<<pn->value<<"\t";//输出元素值
pl=new list;
pl->pn=pn;//根节点入栈
pl->next=ps->top;
ps->top=pl;
pn=pn->left;//左节点
}
else{
pl=ps->top;
ps->top=ps->top->next;//弹出栈中左结点元素
pn=pl->pn->right;
delete pl;//删除左结点
}
}
}
cout<<endl;
}

void travel_level_binary_tree(pnode pn)//二叉树层次遍历
{
if(pn!=NULL){//队列初始信息设置
pqueue pq=new queue;//队列
plist pl=new list;//链表
pl->pn=pn;
pq->head=pl;
pq->tail=NULL;//链表尾部
pq->head->next=pq->tail;
plist pltmp=pl;//用在存放最有一个有用的地址指针

while(pq->head!=pq->tail){
cout<<pq->head->pn->value<<"\t";
if(pq->head->pn->left){
pl=new list;
pl->pn=pq->head->pn->left;

pltmp->next=pl;
pltmp=pl;
pltmp->next=pq->tail;
}
if(pq->head->pn->right){
pl=new list;
pl->pn=pq->head->pn->right;

pltmp->next=pl;
pltmp=pl;
pltmp->next=pq->tail;
}
pl=pq->head;
pq->head=pq->head->next;
delete pl;
}
cout<<endl;
}
}
int main()
{
srand((unsigned int)time(NULL));
int maxDep;
while(maxDep=rand()%10,maxDep<3);
pnode pn;
maxDep=6;
build_binary_tree(pn,0,maxDep);//构建二叉树
cout<<endl;
travel_level_binary_tree(pn);//层次遍历-队列实现
travel_recursive_binary_tree(pn);//前序遍历
cout<<endl;
travel_stack_binary_tree(pn);//递归遍历-堆栈实现
}