二叉树的非递归遍历

建立二叉链表存储结构，创建二叉树。利用栈实现非递归中序遍历。

输入序列为：1 2 0 4 0 0 3 5 0 0 0 

#include<stdio.h>#include<iostream>#include<malloc.h>#define TRUE 1#define FALSE 0#define ok 1#define maxsize 100using namespace std;typedef struct binode{int data;struct binode *lchild,*rchild;}binode,*bitree;typedef struct {binode *a[maxsize];int top;}sqstack;int treecreated=FALSE;int creatbitree(bitree *T);void nrinordertraverse(bitree T);void push(sqstack *s,binode *x);binode *pop(sqstack *s);void main(){int choice=0,flag;int leave=FALSE;binode * BT;cout<<"========利用栈实现非递归遍历演示程序=========="<<endl;do{cout<<"1.创建一个二叉树，按先序遍历结果输入，空用0表示"<<endl;cout<<"2.中序遍历二叉树，非递归方式遍历二叉树"<<endl;cout<<"0.quit"<<endl;cout<<"-----input your selection:";cin>>choice;switch(choice){case 1:if(treecreated){cout<<"sorry,the tree has been already created!"<<endl;break;}cout<<"please put in number!"<<endl;flag=creatbitree(&BT);if(flag==ok){cout<<"okey,now a tree named BT is created.."<<endl;treecreated=TRUE;}case 2:cout<<"in nrorder:";nrinordertraverse(BT);cout<<endl;break;case 0:leave=TRUE;break;}}while(!leave);cout<<"thanks for using ,bye~"<<endl;}int creatbitree(bitree *T){int ch=0;cin>>ch;if(ch==0)(*T)=NULL;else{(*T)=(bitree)malloc(sizeof(binode));(*T)->data=ch;creatbitree(&(*T)->lchild);creatbitree(&(*T)->rchild);}return ok;}void nrinordertraverse(bitree T){sqstack s;binode *p;s.top=0;push(&s,T);while(s.top!=0){while(s.a[s.top]!=NULL){p=s.a[s.top];push(&s,p->lchild);}p=pop(&s);if(s.top!=0){p=pop(&s);cout<<p->data<<"   ";push(&s,p->rchild);}}cout<<endl;}void push(sqstack *s,binode *x){if(s->top==maxsize)cout<<"stack overflow!"<<endl;else{s->top++;s->a[s->top]=x;}}binode *pop(sqstack *s){binode *x;if(s->top==0){cout<<"stack underflow"<<endl;return(NULL);}else{x=s->a[s->top];s->top--;return(x);}}