类似前序遍历 建立二叉树

例如输入AB##C##

输出前序遍历为ABC

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

# define maxn 100

int n=0,len;                         

struct node

{

         char data;

         struct node *lchild;

         struct node *rchild;

};

 typedef struct node NODE ;char a[maxn];

 int main() 

{

         NODE * creat();

         void preorder(NODE *root);

         scanf("%s",a);

         len=strlen(a);

         preorder(creat());

         printf("\n");

}

 

NODE * creat()                 //递归建立二叉树

{

         NODE *t;

         t=(NODE *)malloc(sizeof(NODE));

         if(n>=len)

         {

                   t=NULL;

         }

         if(a[n]!='#')

         {

                   t->data=a[n];

                   n++;

                   t->lchild=creat();

                   t->rchild=creat();

         }

         else

         {

                   n++;

                   t=NULL;

         }

         return t;

 

}

 

void preorder(NODE *root)        //前序遍历

{                                    

          if(root==NULL)

         {

                   return ;

         }

         else

         {

                   printf("%c",root->data);

                   preorder(root->lchild);

                   preorder(root->rchild);

         }

}