请教高手，指出错误，感谢啦

#include"stdio.h"
#include"malloc.h"
int main()
{  typedef struct node{
    char data;
    struct node*next;
    }LinkList;
   LinkList *head,*s,*r,*letter,*digital,*other,*q,*p1,*p2,*p3;
   char ch;
   head=(LinkList*)malloc(sizeof(LinkList));
   digital=(LinkList*)malloc(sizeof(LinkList));
   letter=(LinkList*)malloc(sizeof(LinkList));
   other=(LinkList*)malloc(sizeof(LinkList));
   r=head;
   while (ch!='$'){
     s=(LinkList *)malloc(sizeof(LinkList));//创建结点放入字符
     s->data=ch;
     r->next=s;    //
     r=s;        //
     ch=getchar();
   }
   r->next=NULL;
   q=head->next;
   p1=digital;
   p2=letter;
   p3=other;
    do{if((q->data>='0')&&(q->data<='9'))//选出数字字符
        {   head->next=q->next;
            p1->next=q;
            p1=p1->next;
            q=head->next;
        }
        else if(((q->data>='a')&&(q->data<='z'))||((q->data>='A')&&(q->data<='Z')))//选出字母字符
           {
            head->next=q->next;
            p2->next=q;
            p2=p2->next;
            q=head->next;
            }
            else {
              head->next=q->next;
              p3->next=q;
              p3=p3->next;
              q=head->next;
              }
          }while(q!=NULL);
   while(digital!=NULL){    //分别输出三个链表
    printf("%C ",digital->data);
    digital=digital->next;}
    printf("\n");
   while(letter!=NULL){
    printf("%C ",letter->data);
    letter=letter->next;}
    printf("\n");
   while(other!=NULL){
    printf("%C ",other->data);
    other=other->next;}
    printf("\n");

}