djb2 hash function.c

// Djb2 hash function
unsigned long hash(char *str) {

        unsigned long hash = 5381;
        int c;
        while ((c = *str++))
            hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
        return hash % NUM_BUCKETS;

}

hi I'm noob what does while ((c=*str++)) means?

Hi,

In C when you do an assignment like x = 2, it's considered a function, so if(x = 2) would be evaluated as true.

Now if we break down the statement in the while we:

• de-reference str (*str), in other words, we get the character at this address in the string.
• we assign the value to c.
• we advance the str pointer to the next character (str++).
  As said earlier, the character assigned to c gets evaluated as a boolean, the last character of a C string '\0' is evaluated to false so the while loop exits when reaching the end of the string.

Hope that helped!

Thanks for the code! helped me build a hash table for CS50 course.