Access violation reading location 0xFFFFFFF8 on second usage of method

Question

so I have exception while I try to rehash hashtable second time

here is my rehash Method.

void ReHash()
{
    if (currentSize >= maxSize * 0.8) {
        int tempSize = maxSize * 2;
        cout << "rehash" << endl;
        list<T>* tempArr = new list<T>[tempSize];
        Node<T>* temp = NULL;
        int index = 0;
        for (int i = 0; i < maxSize - 1; i++)
        {

            if (arr[i].getSize() > 0) {
                for (int j = 0; j < arr[i].getSize(); j++) {
                            temp = arr[i].getDataFromSpecificNode(j);
                            if (temp != NULL) {
                                index = hashFunction(temp->key);
                                tempArr[index].addAtTail( temp->getData(), temp->key);
                                break;
                            }
                        }
                }
            }
        
        delete[] arr;
        maxSize = maxSize * 2;
        arr = new list<T>[maxSize];
        arr = tempArr;
        delete[] tempArr;

    }

}

I'm pretty sure that rehash method is the one that causes problems. Thats why I would like to ask if am deleting smth wrong?

here some bigger sample if needed: http://coliru.stacked-crooked.com/a/d1bd6308849f153e

thank you for any Feedback.

Answer 1

You're both creating and deleting something wrong.

First, you create one array,

list<T>* tempArr = new list<T>[tempSize]

then you create another one,

arr = new list<T>[maxSize];

which you immediately throw away (leak) by pointing to the first array you created instead,

arr = tempArr;

and lastly, you make sure that arr is an invalid pointer by deleting what it points to ( arr and tempArr have the same value at this point),

delete[] tempArr;

There should be one new - for the new array - and one delete [] , for the old array.

At the end of the function, you need to release your previous array:

delete [] arr;

then "take over" the first array you created:

arr = tempArr;

and adjust your size:

maxSize = maxSize * 2;