Pset5 incomplete definition of type struct node

Question

EDIT:

I've changed my struct to match what's in the video as thus in my header file:

typedef struct{
    bool end;
    struct node* child[27];
}node;

And in my C file when I do:

if(trav->child[cIndex]!=0){
                printf("Child node is empty\n");
                trav->child[cIndex] = trav;

I get:

dictionary.c:84:41: error: incompatible pointer types assigning to 'struct node *'
 from 'node *' [-Werror,-Wincompatible-pointer-types]
                trav->child[cIndex] = trav;

Node* trav is malloced properly just liket he root node. Why is the compiler thinking one's a "node*" and the other is "struct node*"?

Also, how do you initialize the values of a node? I did:

node* root;
root = malloc(sizeof(node));
root = 0;

Which, I hope initializes the boolean and the elements of the child node array to 0. Is this a correct assumption to make?

-----------END EDIT----------------

I am using the trie method and have the usual typedef here:

typedef struct{
    bool end;
    struct node* child[27];
}node;

But when I do

struct node* root;
root = (struct node *) malloc(sizeof(node));
root->end = false;

I am getting:

dictionary.c:47:9: error: incomplete definition of type 'struct node'
root->end = false;

Any ideas would be appreciated.

Answer 1

The definition of struct node is incomplete in struct node itself.

To fix this, you need to define struct node like this:

typedef struct node{
    bool end;
    struct node* child[27];
}node;

Now, child will know what it is. :)

You need to do typedef struct name { /* struct */ } name; whenever you have a self-referencing struct.

Answer 2

Are you trying to define a new struct? The command struct node* root; is an attempt to do so. You've previously defined a struct with the typedef command.

Instead, just remove the word struct and do this:

 node* root;
 root = malloc(sizeof(node));

This creates a variable called root that is a pointer to a node structure.

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