我的结构代码中出现双重自由错误

Question

我试图编写一个删除列表中某些节点的结构，删除功能正常工作，但我得到一个双重免费错误。

我无法弄清楚哪个免费给了我这个问题。我很感激任何帮助

struct dog* delete_from_list(struct dog *dogs)
{
    int number2 = 0;

    struct dog *temp, *cur = dogs;

    if (dogs==NULL)
    {
        printf("There are no dogs on the list \n");
        return 0;
    }

    printf("Enter patient number to delete: \n");
    scanf("%d", &number2);

    if (dogs->number==number2)
    {
        if(dogs->next==NULL) //only one node in the list
        {
            free(dogs);
            return NULL;
        }
        dogs = dogs->next; //moves the head to next node
        free(cur);
        return dogs;
    }
    else
    {
        while (cur->next != NULL && cur->next->number != number2)
        {
            cur = cur->next;
        }

        if(cur->next==NULL)
        {
            printf("Dog with number %d is not present \n", number2);
            return dogs;
        }

        temp = cur->next;
        cur->next = cur->next->next;
        free(temp);
        return dogs;
    }
}

Answer 1

为避免双重误差，请尝试以下操作：

• 在 free指针后右，将其设置为NULL
• 在 free指针前右，检查它是否为NULL

我会尝试删除特殊外壳的数量，例如

typedef struct dog Node;

Node * delete_from_list(Node * head) {
  const int key_to_delete = GetKeyToDelete();
  if (!head) return NULL;
  for (Node * cur = head; cur; ) {
    if (cur->key = key_to_delete) {
      Node * curnext = cur->next;
      free(cur);
      cur = curnext;
    } 
    else {
      break;
    }
  }
  Node * new_head = cur;
  for (Node * cur = new_head; cur; cur = cur->next) {
    if (cur->next && (cur->next->key == key_to_delete)) {
      Node * curnextnext = cur->next->next;
      free(cur->next);
      cur->next = curnextnext;
    }
  }
  return new_head;
}