下面C语言程序的  p=n->head->next;  用gdb调试的时候报错，Program received signal SIGSEGV, Segmentation fault.
0x0804919b in simplify_polynomial (n=0x804c188) at test7.c:475
475       p=n->head->next; 找了很久没发现错误在哪里。 请问错误在哪里？ 完整程序在：http://hi.baidu.com/lijr03/blog/item/dd824f7e2cb804f42e73b3a1.html。谢谢



polynomial simplify_polynomial(polynomial n)
{
   polynomial p;
   polynomial_node *p1, *s;
 
  
   p=n;
   p=n->head->next;
   while(p!=NULL)
   {
        p->m=simplify_monomial(p->m);
        p=p->next;
   }

   p1=p->head->next;
   p=p->head->next;
   s=p;
   
   while(p!=NULL)          /* merge the terms with the same monomials */
   {
      while(p1!=NULL)
      {
          if(compare_monomials(p->m, p1->m)==1)
          {
               p->m->coeff=p1->m->coeff + p->m->coeff;
               p=delete_monomial(p, p1->m);
               p1=s;
            
               p=s->next;
          }
          p1=p1->next;
      }
      p=p->next;
      s=p;           /* s records the position of p */
      p1=p;
   }

   
   p1=p->head->next;
   while(p1 != NULL)
   {
      if(p1->m->coeff==0)
      {
         p=delete_monomial(p, p1->m);
      }
      p1=p1->next;
   }
   
   return p;
  
}

请楼主自己把代码贴过来