数据结构实验7

题目：假设二叉树采用链接存储方式存储，分别编写一个二叉树先序遍历的递归算法和非递归算法。

test.h

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
#define MAX 128
typedef struct biTreeNode
{
    char data;
    struct biTreeNode *lchild,*rchild,*parent;
}biTreeNode, *bi;
bi s[MAX];
char node[]={'a','b','d','h','#','#','I','#','#','E','#','#','c','f','#','#','g','j','#','#','k','#','#'};
//char node[]={'A','B','#','D','#','#','C','#','#'};
//建树
biTreeNode *creatBiTree(biTreeNode *T)
{
    char ch;
    static int i=0;
    ch=node[i];
    i++;
    if(ch=='#')
    {
        T=NULL;
    }
    else
    {
        T=(biTreeNode *)malloc(sizeof(biTreeNode));
        if(!T)
            exit(0);
        T->data=ch;
        T->lchild=creatBiTree(T->lchild);
        T->rchild=creatBiTree(T->rchild);
    }
    return T;
}

//递归遍历
void preOrder(biTreeNode *T)
{
    if(T==NULL)
        return;
    else
    {
        printf("%c ",T->data);
        preOrder(T->lchild);
        preOrder(T->rchild);
    }
}
void nPreOrder(struct biTreeNode *bt)
{
int    top=-1; //采用顺序栈，并假定不会发生上溢
    while(bt!=NULL || top!=-1) //两个条件都不成立才退出循环
    {
        while(bt!=NULL) 
        {
            printf("%c ",bt->data);
            s[++top]=bt; //将根指针 bt 入栈
            bt=bt->lchild;
        }
       if(top!=-1) //栈非空
        {
            bt=s[top--];
            bt=bt->rchild;
        }
    }
}

test.c

#include"test.h"
int main()
{

    biTreeNode *T;
    T = creatBiTree(T);
    printf("递归：\n");
    preOrder(T);
    printf("\n非递归：\n");
    nPreOrder(T);
    return 0;
}