CODEWITHSUNDEEP
cpointers
hannah
hannah

Reputation: 909

Incompatible pointer type and struct issues

#define HASH_SIZE 5

// prototype
int hash(char *word);

// counter
int counter;

// node
typedef struct node
{
    char word[LENGTH + 1];
    struct node *next;
} node;

// hash table
struct node *hashtable[HASH_SIZE];
  bool
load(const char *dictionary)
{
    // open the dictionary
    FILE *dict = fopen(dictionary, "r");
    if(dict == NULL)
    {
        printf("Could not open %s.\n", dictionary);
        return false;
    }

    // set all values in the hash table to null
    for(int i = 0; i < HASH_SIZE; i++)
    {
        hashtable[i] = NULL;
    }

    // set the counter to 0
    counter = 0;

    // iterate through the words in the dictionary
    while (!feof(dict))
    {
        //declare a node
        node *n = malloc( sizeof(node) );

        // copy the word into the node
        fscanf(dict, "%s", n.word);

        // hash the word
        int hash_value = hash(n.word);

        // start saving addresses to the hashtable
        n.next = hashtable[hash_value];
        hashtable[hash_value] = &n;

        // that's one more!
        counter++;
    }


    fclose(dict);

    return true;
}

For the following lines:

        //declare a node
    node *n = malloc( sizeof(node) );

// hash the word
    int hash_value = hash(n.word);

    // start saving addresses to the hashtable
    n.next = hashtable[hash_value];
    hashtable[hash_value] = &n;r code here

I receive the following error messages:

dictionary.c: In function 'load':
dictionary.c:112:29: error: request for member 'word' in something not a structure or union
dictionary.c:135:32: error: request for member 'word' in something not a structure or union
dictionary.c:138:10: error: request for member 'next' in something not a structure or union
dictionary.c:139:31: error: assignment from incompatible pointer type [-Werror]

What's the issue?

Upvotes: 2

Views: 1023

Answers (1)

Ernest Friedman-Hill
Ernest Friedman-Hill

Reputation: 81684

Really simple:

node *n = malloc( sizeof(node) );
fscanf(dict, "%s", n.word);

n is a pointer to a node, but n.word implies that n itself is a node. For a pointer, the syntax is a little different. 

fscanf(dict, "%s", n->word);

Upvotes: 3

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