Hashing

• String hash function 

• Recall that the Java String function combines successive characters by multiplying the current hash by 31 and then adding on the new character. 

  int hash = 0; for (int i = 0; i < length(); i++) { hash = 31 * hash + charAt(i); } return hash;

•  Probably a pretty decent hash algorithm, as presented in K&R version 2 (verified by me on pg. 144 of the book); NB: be sure to remove % HASHSIZE from the return statement if you plan on doing the modulus sizing-to-your-array-length outside the hash algorithm. Also, I recommend you make the return and "hashval" type unsigned long instead of the simple unsigned (int).

  unsigned hash(char *s)
  {
      unsigned hashval;
  
      for (hashval = 0; *s != '\0'; s++)
          hashval = *s + 31*hashval;
      return hashval % HASHSIZE;
  }

•