#include<stdio.h>
#include<malloc.h>
#include<string.h>
#define n 10
#define null 0
typedef struct
{
 char data[n];
 int top;
}seqstack;
typedef struct node2
{
 char data;
 struct node2 *lchild;
 struct node2 *rchild;
}btnode;
void main()
{
   btnode *s[n],*b,*p=null;
   int top=-1,tag,j;
   char ch,str[n];
   printf("输入：\n");
     for(j=0;j<n;j++)
        str[j]=getchar();
         ch=str[0];
        while(ch!='\n')
        {
            switch(ch)
            {
             case'(':top++;s[top]=p;tag=1;break;
             case')':top--;break;
              case',':tag=2;break;
               default:p=(btnode *)malloc(sizeof(btnode));
               p->data=ch;
               p->lchild=p->rchild=null;
               if(b==null) b=p;
               else
               {
                      switch(tag)
                      {
                           case 1:s[top]->lchild=p;break;
                             case 2:s[top]->rchild=p;break;
                      }
               }
            }
              j++;ch=str[j];
        }
        if(b!=null)
        printf("%c",b->data);
        else if(b->lchild!=null)
        {printf("%c",p->lchild->data);p=p->lchild;}
        else{printf("%c",p->rchild->data);p=p->rchild;}

}大侠帮忙看看那错了？