assignment to incompatible pointer type double pointer

Question

I am trying to add nodes right after the *add pointer in my linked list my struct and code is as follows, but shows an error in (*add)->next = new_node:

    typedef struct {
    int data;
    struct node* next;
    }node;

    void create_node(node **add,int dat)
    {
        if((*add) == NULL)
        {
            (*add) = (node*)malloc(sizeof(node));
            (*add)->data = dat;
            (*add)->next = NULL;
        }

        else
        {
            node *new_node = (node*)malloc(sizeof(node));
            new_node->data = dat;
            new_node->next = (*add)->next;
            (*add)->next = new_node; //assignment to incompatible pointer type error
        }


    }

(*add)->next = new_node shows incompatible pointer type error — gPats, Apr 22 '17 at 15:25
There is NO need to cast the return of `malloc`, it is unnecessary. See: [**Do I cast the result of malloc?**](http://stackoverflow.com/q/605845/995714) for thorough explanation. — David C. Rankin, Apr 22 '17 at 15:28
@Gautam You fixed your code and now the error you're asking about is gone. — Emil Laine, Apr 22 '17 at 15:28

score 1 · Accepted Answer · answered Apr 22 '17 at 15:23

You're declaring next as a pointer to struct node, but there's no struct node in your code (only the typedef node).

You need to give a name for the struct in order to refer to it in the declaration of next:

typedef struct node {

Currently struct node refers to a different, unrelated struct (that you haven't defined).

assignment to incompatible pointer type double pointer

1 Answers1