可扩展哈希-析构函数C ++

Question

So... I have implemented a version of exendible hashing...my question now is for the destructor.

I used in the Hash class an array of pointers that point on buckets from class Bucket. The problem is there can be multiple pointers on the same bucket.

In the destructor of the Hash class I have to delete every bucket and then the array, but I have to be careful not to delete the same bucket twice (I think that'll result in an error). In order to do that I used a bool vector to memorize whether or not the bucket has already been deleted.

My question is now: is there a way to know if a bucket has already been deleted without using more memory (the bool vector) ?

LE: I solved the destructor problem using nullptr (seems to be working now), but...another question: how can I go through every bucket exactly 1 time (for finding the min and max elements, for example). I can't use nullptr this time (the pointers need to stay where they are - on the buckets)

Answer 1

Just iteratively use your erase function

while (size ())
{
    erase(begin());
}

Answer 2

I used in the Hash class an array of pointers that point on buckets from class Bucket. The problem is there can be multiple pointers on the same bucket.

My question is now: is there a way to know if a bucket has already been deleted without using more memory (the bool vector) ?

Sure -- use reference counting. Put an integer member variable in the Bucket class, initialized to zero. Whenever you create a pointer to that Bucket object, increment the integer. Whenever you invalidate a pointer to the Bucket (ie whenever you would have called delete on that pointer), decrement the integer member variable. If that decrement causes the integer to become zero, you know the Bucket has no more pointers pointing to it, so delete the Bucket.