UNIT 4: Hashing and File Structure
A hash table is a data structure that is used to store keys/value pairs.It uses a hash
function to compute an index into an array in which an element will be inserted or
searched. By using a good hash function, hashing can work well.
Hash Table is a data structure which stores data in an associative manner. In a
hash table, data is stored in an array format, where each data value has its own
unique index value. Access of data becomes very fast if we know the index of the
desired data.
Thus, it becomes a data structure in which insertion and search operations are very
fast irrespective of the size of the data. Hash Table uses an array as a storage
medium and uses hash technique to generate an index where an element is to be
inserted or is to be located from.
Hashing
Hashing is a technique to convert a range of key values into a range of indexes of
an array. We're going to use modulo operator to get a range of key values.
Consider an example of hash table of size 20, and the following items are to be
stored. Item are in the (key,value) format.
(1,20)
(2,70)
(42,80)
(4,25)
(12,44)
