C error: dereferencing pointer to incomplete type linked list

Question

In my c program I creating a singly linked list where we have to insert a node using the prev node, I'm getting this error in my main() function:

Dereferencing pointer to incomplete type ‘struct Node’

I am not sure why is it giving that error.

while((temp->next != NULL) && (temp->next->data < randomNumData)) -- error here

typedef struct _Node
{       
        int data;
        struct Node *next;
} ListNode;

ListNode *newList();
ListNode *insertNode(ListNode *prev, int data);

int main()
{
        ListNode *head = newList();

        int randomNumData;
        ListNode *temp = head;
        int i;

        for(i = 0; i < 11; i++)
        {
                randomNumData = random()%1001;
                while((temp->next != NULL) && (temp->next->data < randomNumData))
                {
                        temp = temp->next;
                }
                temp->data = randomNumData;
                head = insertNode(temp, randomNumData);
        }

        printList(head);
}

// returning the head of a new list using dummy head node
ListNode *newList()
{
        ListNode *head;
        head = malloc(sizeof(ListNode));
        if(head == NULL)
        {
                printf("ERROR");
                exit(1);
        }

        head->next = NULL;
        return head;
}

ListNode *insertNode(ListNode *prev, int data)
{
        ListNode *temp = prev;
        prev->next = temp->next;
        temp->next->data = data;

        return temp;
}

Please provide an example which builds. Where is the definition of ListNode? — Steve
– Steve, Commented Oct 27, 2017 at 13:29
You've declared struct Node *next; but there is no struct Node defined anywhere. — melpomene
– melpomene, Commented Oct 27, 2017 at 13:34

Marek Klein · Accepted Answer · 2017-10-27 13:57:34Z

2

You are missing underscore when declaring next.

typedef struct _Node
{       
    int data;
    struct _Node *next;
} ListNode;

answered Oct 27, 2017 at 13:57

Marek Klein

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Comments

samthegolden · Accepted Answer · 2017-10-27 13:48:23Z

0

It looks like you don't have a struct called Node. Import it from other file or just implement it. C is good but it's not a magician so far.

answered Oct 27, 2017 at 13:48

samthegolden

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