[SOLVED] Can someone explain to me how this HASH FUNCTION works (also if they have another better option)?

Can someone explain to me how this HASH FUNCTION works (also if they have another better option)?

I'm working on CS50's pset 5, speller. I need a hash function for a hash table that will efficiently store all of the words on the dictionary (~140,000). I found this one online, but I don't understand how it works. I don't know what << or ^ mean. Here is the hash function, thank you! (I would really appreciate it if you could help me :))

int hash_it(char* needs_hashing)
{
    unsigned int hash = 0;
    for (int i=0, n=strlen(needs_hashing); i<n; i++)
        hash = (hash << 2) ^ needs_hashing[i];
    return hash % HASHTABLE_SIZE;
}

Solution

Those two are Bit-wise operators. These are easy to learn and must to learn for a programmer.

<< - is a binary left shift operator.

Suppose variable "hash" binary is "0011".

hash << 2 becomes "1100".

And ^ is XOR operator. (If set in only one operand ...not in both)

Suppose in your code

hash << 2 gives "1100"

needs_hashing[1] gives "1111"

then

(hash << 2) ^ needs_hashing[i] gives "0011"

For a quick understanding bitwise operators, quickly walk here https://www.tutorialspoint.com/cprogramming/c_bitwise_operators.htm