CODEWITHSUNDEEP
cpointerscastingstructure
Learning C
Learning C

Reputation: 689

How would I print this?

Please look at my last line. How would I print this? How do I cast it? do I cast it (word*)table_p -> buckets_array[0] -> data -> key and (word*)table_p -> buckets_array[0] -> data -> frequency ?

typedef struct data_{
  char *key;
  void *data;
  struct data_ *next;
}data_el;

typedef struct hash_table_ {
  /* structure definition goes here */
  data_el **buckets_array;
} hash_table, *Phash_table;

typedef struct word_{
  char key[WORD_SIZE];
  int frequency;
} word;

word *new_word;
new_word = (word *)malloc(sizeof(word));

new_word->frequency = 5;
new_word->key = "Lalalal";

Phash_table table_p;
table_p = (Phash_table)malloc(sizeof(hash_table));
table_p->buckets_array = (data_el **)malloc(sizeof(data_el *)*(size+1));
table_p->buckets_array[0]->data = (void*)new_word;

/*Is this right? How do I cast this? (word*) ?*/
printf("Key :%s Frequency:%d ",table_p->buckets_array[0]->data->key,
            table_p->buckets_array[0]->data->frequency);

Upvotes: 0

Views: 110

Answers (1)

violet313
violet313

Reputation: 1932

Here you go. Several mistakes were fixed along the way, and this includes the insane cast you're looking for:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define WORD_SIZE 1024

typedef struct data_{
  char *key;
  void *data;
  struct data_ *next;
}data_el;

typedef struct hash_table_ {
  /* structure definition goes here */
  data_el **buckets_array;
} hash_table, *Phash_table;

typedef struct word_{
  char key[WORD_SIZE];
  int frequency;
} word;

int main()
{

int size=0;
word *new_word;
new_word = (word *)malloc(sizeof(word));

new_word->frequency = 5;
strcpy(new_word->key, "Lalalal");
//      ^ ^ ^ ^               - ooops! you need to copy lalalal bytes into key[] array   

Phash_table table_p;
table_p = (Phash_table)malloc(sizeof(hash_table));
table_p->buckets_array = (data_el **)malloc(sizeof(data_el *)*(size+1));


table_p->buckets_array[0] = (data_el *)malloc(sizeof(data_el));
//      ^ ^ ^ ^                - ooops! you might need some data_el

table_p->buckets_array[0]->data = (void*)new_word;


/*Is this right? How do I cast this? (word*) ?*/
word* pdata=table_p->buckets_array[0]->data;
//      ^ ^ ^ ^                - the readable way

printf("Key :%s Frequency:%d ",((word*)(table_p->buckets_array[0]->data))->key, //<--the insane cast way (promote void* data_el.data to a word*)
            pdata->frequency);

            return 0;
}

Upvotes: 1

Related Questions