'/' : illegal, left operand has type 'struct node *'是什么意思?

Question

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define NODE struct node
#define HEAD struct head

NODE
{
 int data;
 NODE *next;
};

HEAD
{
 int count;
 NODE *first;
 NODE *last;
 NODE *sum;
 NODE *max;
 NODE *min;
 NODE *avg;
};

void init(HEAD *head)
{
 head->count = 0;
 head->first = NULL;
 head->last = NULL;
 head->sum = NULL;
}

void addNode(HEAD *head, int data)
{
 HEAD *s;
 NODE *b;
 int min, n;
 int avg;

 s = (HEAD *) malloc (sizeof(HEAD));
 b->data = n;

 if (data < min)
  min = data;

 b->next = s->first;
 s->first = b;
 s->sum += b->data;
 s->count ++;
 s->avg = s->sum / s->count;

 
}

void appendNode(HEAD *head, int data)
{
 HEAD *q;
 NODE *b;
 int max, n;
 int avg;

 q = (HEAD *) malloc (sizeof(HEAD));
 b->data = n;
 b->next = NULL;

 if (data > max)
  max = data;

 if (emptyList(head))
  head->first = b;
 else
  q->last->next = b;

 q->last = b;
 q->count ++;
 q->sum += b->data;
 q->avg = q->sum / q->count;

}

int emptyList(HEAD *head)
{
 if (head->count==0)
  return 1;
 else
  return 0;
}

int listCount(HEAD *head)
{
 return (head->count);
}

void printList(HEAD *head)
{
 int i;
 NODE *prnNode;
 prnNode = head->first;
 for (i=1; i<=head->count; i++)
 {
  printf("%d\n", prnNode->data);
  prnNode = prnNode->next;
 }

}

void prnList(HEAD *head)
{
 NODE *prnNode;

 prnNode = head->first;

 while (prnNode != NULL)
 {
  printf("%d\n", prnNode->data);
  prnNode = prnNode->next;
 }
}

void main()
{
 HEAD *q, *s;
 int i, n;

 q = (HEAD *) malloc (sizeof(HEAD));
 s = (HEAD *) malloc (sizeof(HEAD));
 init(q);
 init(s);

 srand(time(NULL));
 for (i=1; i<20; i++)
 {
  n = rand() % 201 + 100;
  if(n % 2 == 0)
   appendNode(q, n);
  else
   addNode(s, n);
 }

 printf("\n Queue: \n");
 prnList(q);
 printf("\n Stack: \n");
 prnList(s);

 printf("\n\n\t count \t max \t min \t avg \n");
 printf("Queue:\t %d \t %d \t \t %.2f \n", q->count, q->max, q->avg);
 printf("Stack:\t %d \t %d \t \t %.2f \n", s->count, s->min, s->avg);

 printf("\n\n");

}

求帮忙看看怎么改错啊！谢谢你啦！

Answer 1

s->avg = s->sum / s->count; sum和avg是node类型不能使用/，应该是s->avg->data=s->sum->data/s->count;  q->avg = q->sum / q->count;也是  链表不是这样建立的，imooc有视频