Creating array of pointers

Question

I need to create an array to pointers of pNodes but when i declare it i dont know the length of the array

lets see what i mean

this is the Node struct

typedef struct _Node {
    struct _Node* next;
    pElement element;
} Node, *pNode;

this is the Hash struct

typedef struct _Hash {
    int hashSize;
    pNode *hashTable;
}Hash,*pHash;

now i want each of the hashTable boxes to point to a pNode

the problem is that i dont know the size of the array, if i did it would be like (i guess)

pNode hashTable[hashSize]

the way i wrote it and tried to resett all boxes to NULL:

this is the CODE:

allocation memory:

pHash hash = (pHash)(malloc(sizeof(Hash)));
hash->hashTable = (pNode)(malloc(sizeof(pNode) * size));
hash->hashSize = size;
resetHashTable(hash->hashTable, size); // reseting the array to NULLS

the func:

static void resetHashTable(pNode *hashTable, int size) {
    int i;
    for (i = 0; i < size; i++) {
        hashTable[i] = (pNode)NULL;
    }
}

one of the many many errors i get from the program is (the first error)

hash.c:37:18: warning: assignment from incompatible pointer type [enabled by default]
  hash->hashTable = (pNode)(malloc(sizeof(pNode) * size));

can i have some pointers how i need to write it?

You're casting the result of malloc to a pNode, and then try to assign it to hashTable which is a pNode*. — Michael
– Michael, Commented Dec 19, 2014 at 13:21
Do you get a warning about the extra comma in your declarations of pNode and pHash? (you should) — William Pursell
– William Pursell, Commented Dec 19, 2014 at 13:21

Iharob Al Asimi · Accepted Answer · 2014-12-19 13:32:29Z

4

If this is not C++ just don't cast malloc, you have an error in this line

hash->hashTable = (pNode)(malloc(sizeof(pNode) * size));

It could be

hash->hashTable = (pNode *)(malloc(sizeof(pNode) * size));
                    //   ^ hashTable is declared pNode *

A better solution would be

hash->hashTable = malloc(sizeof(pNode) * size);

answered Dec 19, 2014 at 13:32

Iharob Al Asimi

53.1k6 gold badges66 silver badges100 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Karthikeyan.R.S · Accepted Answer · 2014-12-19 13:38:39Z

3

You are declared the pNode as a pointer. Then in Hash structure You are declared the pNode * hastable So you have to use the double pointer **. Or else make that as single pointer in hash structure.

 hash->hashTable = (pNode*)(malloc(sizeof(pNode) * size));

answered Dec 19, 2014 at 13:38

Karthikeyan.R.S

4,0512 gold badges21 silver badges31 bronze badges

Collectives™ on Stack Overflow

Creating array of pointers

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related