Question

For class I need to make a dynamically expanding hash table that expands when the number of bindings reaches certain values – 509,1021, 2039, 4093, etc. I understand just about everything else but I’m not sure how to check which value the table should expand to next.

I think that we’re supposed to use enumerations, but I don’t understand how to get the “next” enumeration value. I.e., if my hash table currently has 1022 bindings I should expand the underlying array to size 2039, but how do I know how to do that? Or am I approaching this the wrong way?

Sorry in advance if this is a stupid question, but it’s not addressed in my book and I’m still very new when it comes to C.

Answer 1

You can’t use enumerations for this purpose in C.

You probably want to put the thresholds in a constant array, and maintain an index to point at the current threshold:

const int thresholds[] = { 509, 1021, 2039, 4093 };

int i_thresh = 0;

...

if (num_elements > thresholds[i_thresh])
{
    i_thresh++;
}