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Asked: 2026-05-19T01:55:15+00:00

I understand that some hash tables use buckets, which is a linked list of

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I understand that some hash tables use “buckets”, which is a linked list of “entries”. 

HashTable
  -size    //total possible buckets to use
  -count   // total buckets in use
  -buckets //linked list of entries

Entry
  -key   //key identifier
  -value // the object you are storing for reference
  -next  //the next entry

In order to get the bucket by index, you have to call:

myBucket = someHashTable[hashIntValue]

Then, you could iterate the linked list of entries until you find the one you are looking for or null.

Does the hash function always return a NUMBER % HashTable.size? That way, you stay within the limit? Is that how the hash function should work?

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1 Answer

  1. Editorial Team

    Mathematically speaking, a hash function is usually defined as a mapping from the universe of elements you want to store in the hash table to the range {0, 1, 2, .., numBuckets – 1}. This means that in theory, there’s no requirement whatsoever that you use the mod operator to map some integer hash code into the range of valid bucket indices.

    However, in practice, almost universally programmers will use a generic hash code that produces a uniformly-distributed integer value and then mod it down so that it fits in the range of the buckets. This allows hash codes to be developed independently of the number of buckets used in the hash table.

    EDIT: Your description of a hash table is called a chained hash table and uses a technique called closed addressing. There are many other implementations of hash tables besides the one you’ve described. If you’re curious – and I hope you are! 🙂 – you might want to check out the Wikipedia page on the subject.

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