Initializing a char* value within struct within a struct in C - c

Question

I have been looking online but so far nothing has helped me understand my problem. Currently I am trying to make two lists that each contain a list of words. Each space contains a word struct and within each word struct is list of 30 doc_list structs. I have been able to allocate memory and store a char*s within the word list struct but when I try to allocate memory and store a char* within a doc_list struct I get a segmentation error. I am confused because I declared my doc_list struct the same exact way as I did my word_list struct.
Below is the initialization of my structs
In my C file I initialize my Hash Table
#define BUFFSIZE 1000
#define STOPLIST_INDEX 0
#define DOCUMENTS_INDEX 1
struct HashTable{
int tableSize;
struct word_list** wordList;
};
struct word_list{
char* word;
struct doc_list** docList;
};
struct doc_list{
char* docName;
int timesAppear;
};
//Initialing lists associated with hash table
struct HashTable** initialize_hash_table(int argc, char** argv)
{
int k; //HashTables
int i; //Words
int q; //Document names
struct HashTable** hashTable = calloc(2, sizeof(struct HashTable **));
for(k =0; k < 2; k++)
{
hashTable[k] = calloc (1, sizeof(struct HashTable *));
hashTable[k]->wordList = calloc(BUFFSIZE, sizeof(struct word_list **));
for(i = 0; i < BUFFSIZE; i++)
{
hashTable[k]->wordList[i] = calloc(1, sizeof(struct word_list *));
hashTable[k]->wordList[i]->docList = calloc(30, sizeof(struct doc_list**));
for(q = 0; q < 30; q++)
{
hashTable[k]->wordList[i]->docList[q] = calloc(1, sizeof(struct doc_list*));
}
}
}
return hashTable;
}
then in my insert function where I store the document name char* value is where I get a segmentation error. I don't understand why this happens because I initialized my doc_list structure the exact same way that I initialized my word_list structure.
int insert(struct HashTable** hashTable, char* document_word, char* filename, int index)
{
//create the hash key
int key = hashFunction(document_word, BUFFSIZE);
//Check if word exists in Stop List
if(index == 0 || hashTable[STOPLIST_INDEX]->wordList[key]->word == NULL)
{
//insert into list
hashTable[index]->wordList[key] = malloc(sizeof(struct word_list*));
hashTable[index]->wordList[key]->word = strdup(document_word);
printf("%s%s\n", "INSERTED VALUE: ", hashTable[index]->wordList[key]->word);
//Add filename to words' document list
int w = 0;
puts("segfaulting here");
puts("1");
hashTable[index]->wordList[key]->docList[w] = malloc(sizeof(struct doc_list*));
hashTable[index]->wordList[key]->docList[w]->docName = strdup(filename);
printf("%s%s\n", "INSERTED ", filename);
printf("\n");
}
return 0;
}
What I believe is happening is that all the word structs are being declared NULL if they are not allocated memory for a word but none of the doc_list structs are being declared NULL for some reason. I allocated memory for them the exact same way I did the word_list structs.
The output when I run the program is this:
Hashing filename:stopwords.txt
---------
INSERTED VALUE: a
segfaulting here
1
Segmentation fault (core dumped)
What am I doing wrong??

Answer 1

Problems I see:
hashTable[k] = calloc (1, sizeof(struct HashTable *));
needs to be changed to
hashTable[k] = calloc (1, sizeof(struct HashTable));
Type of hasTable[k] is struct HashTable*. The object that it points to has to be of size struct HashTable, not struct HashTable*.
There is a similar error in:
struct HashTable** hashTable = calloc(2, sizeof(struct HashTable **));
It needs to be:
struct HashTable** hashTable = calloc(2, sizeof(struct HashTable*));
You won't see the error easily since sizeof(struct HashTable*) is equal to sizeof(struct HashTable**) in most cases.
More of such errors are in initialize_hash_table.
hashTable[k]->wordList[i]->docList = calloc(30, sizeof(struct doc_list**));
needs to be
hashTable[k]->wordList[i]->docList = calloc(30, sizeof(struct doc_list*));
hashTable[k]->wordList[i]->docList[q] = calloc(1, sizeof(struct doc_list*));
needs to be
hashTable[k]->wordList[i]->docList[q] = calloc(1, sizeof(struct doc_list));
You have similar errors in insert.
hashTable[index]->wordList[key] = malloc(sizeof(struct word_list*));
needs to be
hashTable[index]->wordList[key] = malloc(sizeof(struct word_list));
hashTable[index]->wordList[key]->docList[w] = malloc(sizeof(struct doc_list*));
needs to be
hashTable[index]->wordList[key]->docList[w] = malloc(sizeof(struct doc_list));

Answer 2

Tip: Only use calloc if you actually need your memory zeroed. malloc is faster.
Also, there is no need to test unequality to 0 NULL \0, unless you need your truth value normalized to 0|1, and even then !! is preferrable. ! for equality to 0 in any of its guises.
But your real problem is something else:
struct HashTable** hashTable = calloc(2, sizeof(struct HashTable **));
The above line alloates zeroed memory for 2 struct HashTable**, and stores the pointer in hashTable, which has type sttruct HashTable** too!!
You actually want to allocate space for 2 struct HashTable*.
In this one specific case it does not kill you, because those two pointer types happen to use the same amount of space on this architecture, but it's a pattern which is repeated with worse results later, and allocating too little memory leads to buffer overruns, which as Undefined Behavior mean anything can happen (and naturally mostly bad things).
When you want to point with pointer p to a memory block, allocate it thus:
p = malloc(count * sizeof *p);
p = calloc(count, sizeof *p); /* only for zeroed memory */
You do not want to use sizeof on the type, because it is far too easy to get it wrong, adding or leaving off one or more levels of indirection or taking a completely unrelated type.
Unless you name a VLA to sizeof, it will not evaluate its arguments, but only get the type and derive a compile-ime-constant.
Some more things you should read:
How to Debug Small Programs
C99 with Technical corrigenda TC1, TC2, and TC3 included
MCVE