广义表算法(数据结构和算法分析)

#include <stdio.h>
#include <malloc.h>
typedef struct lnode
{
int tag;
union
{
char data;
struct lnode *sublist;
}val;
struct lnode *link;
}GLNode;
GLNode *CreatGL (char *&s)
{
   GLNode *h; char ch;
   ch=*s;
   s++;
   if (ch!='\0')
   { h=(GLNode *)malloc(sizeof(GLNode));
     if (ch=='(')
 {  h->tag=1;
   h->val.sublist=CreatGL(s);
 }
     else if (ch==')')
      h=NULL;
          else 
  { h->tag=0;
    h->val.data=ch;
  }
   }

   else h=NULL;
   ch=*s;
   s++;
   if (h!=NULL)
      if (ch==',')
  h->link=CreatGL(s);
  else
  h->link=NULL;
  return h;
}
void  DispGL (GLNode *g)
{
if (g!=NULL)
{
if (g->tag==1)
{  printf("(");
   if  (g->val.sublist==NULL)
   printf("");
   else 
   DispGL (g->val.sublist);
}
else 
printf("%c",g->val.data);
if (g->tag==1)
printf(")");
if (g->link!=NULL)
{  printf(",");
   DispGL(g->link);
}
}