CODEWITHSUNDEEP
carrayspointers
JohnnyF
JohnnyF

Reputation: 1101

Creating array of pointers

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?

Upvotes: 0

Views: 96

Answers (2)

Karthikeyan.R.S
Karthikeyan.R.S

Reputation: 4041

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));

Upvotes: 3

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53006

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);

Upvotes: 4

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