How to split string and return the sum of every characters integer to the 31 to the power of i

Question

In a hash table map suppose that key is a pointer of a character char *key, which is a string.
Ho do we implement a function that returns split string and return the sum of every characters integer to the 31 to the power of i, where i starts from 0.
For example if our
char *key="abc";
k1=int(key[0]);
k2=int(key[1]);
k3=int(key[2]);
result=k1+31*k2+k3*31^2;

This function should be applied to the
char *key="banana";
depending on the length of the characters.

Answer 1

~ swim ~ actually I have done it, just I was unsure coz that hashcode only was filling to 2 hasmap lists, i thought it was incorrect ,anyways i will check tomorrow ,thanks

Answer 2

~ swim ~ i meant would you please implementing a function maybe recursive or loop idk