二叉树中序遍历

1 递归版

2 迭代版#1

 

3 迭代版#2

 \

4 迭代版#3

待补充

实现

 

#include<queue>
#include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
typedef struct node
{
    struct node *lc;
    struct node *rc;
    char date;
}bintree,*tree;
stack<tree> s;
void createtree(tree &T)
{
    char c;
    cin>>c;
    if(c=='#')
        T=NULL;
    else{
        T=new bintree;
        T->date=c;
        createtree(T->lc);
        createtree(T->rc);
    }
}
void inprint(tree T) // 递归版
{
    if(T){
        inprint(T->lc);
        cout<<T->date;
        inprint(T->rc);
    }
}
void go(tree T)
{
    while(T){
        s.push(T);
        T=T->lc;
    }
}
void intreeprint1(tree T) // 迭代版#1
{
    while(true){
        go(T);
        if(s.empty()) break;
        T=s.top();s.pop();
        cout<<T->date;
        T=T->rc;
    }
}
void intreeprint2(tree T) // 迭代#2，与迭代#1等价
{  while(true){
    if(T){
        s.push(T);
        T=T->lc;
    }
    else if(!s.empty()){
        T=s.top();
        s.pop();
        cout<<T->date;
        T=T->rc;
    }
    else
        break;
}
}
int main()
{
    tree T;
    createtree(T);
    inprint(T);
    cout<<endl;
    intreeprint1(T);
    cout<<endl;
    intreeprint2(T);
}