Good Hash Function for Strings

Question

I'm trying to think of a good hash function for strings. And I think it might be a good idea, to sum up the unicode values for the first five characters in the string (assuming it has five, otherwise stop where it ends). Would that be a good?

Answer 1

Usually hashes wouldn't do sums, otherwise, stop and pots will have the same hash.

And you wouldn't limit it to the first n characters because otherwise house and houses would have the same hash.

Generally, hashes take values and multiply it by a prime number. So you can probably refer this:

int hash = 7;
for (int i = 0; i < strlen; i++) 

{
    hash = hash*31 + charAt(i);
}