Hello, I was wondering if I could get this code explained to me. Also if there was anything incorrect, if it could be fixed. If a sample output is possible, can it be done?

Thank you!

#include

#include

#define MAXSTRING 100

/*

* USAGE:

* gcc hashHarness.c -o hashX

* ./hashX < inputFile.txt

*/

/*

*djb2

* this algorithm (k=33) was first reported by dan bernstein many years ago in comp.lang.c.

* another version of this algorithm (now favored by bernstein) uses

* xor: hash(i) = hash(i - 1) * 33 ^ str[i];

* the magic of number 33 (why it works better than many other constants, prime or not)

* has never been adequately explained.

*

* ref:http://www.cse.yorku.ca/~oz/hash.html

*/

unsigned long hashDJB2(char *str)

{

unsigned long hash = 5381;

int c;

while ((c = *str++))

hash = ((hash << 5) + hash) + c; /* hash * 33 + c */

return hash;

}

/*

* K&R's simple but ...

* This hash function appeared in K&R (1st ed) but at least the reader was warned:

* "This is not the best possible algorithm, but it has the merit of extreme simplicity."

* This is an understatement; It is a terrible hashing algorithm, and it could have been

* much better without sacrificing its "extreme simplicity." [see the second edition!]

* Many C programmers use this function without actually testing it, or checking something

* like Knuth's Sorting and Searching, so it stuck. It is now found mixed with otherwise

* respectable code, eg. cnews. sigh.

*

*/

unsigned long hashKR(char *str)

{

unsigned int hash = 0;

int c;

while ((c = *str++))

hash += c;

return hash;

}

int main(int argc, char *argv[])

{

char *buffer;

int bufferlen = MAXSTRING;

unsigned long newHash;

unsigned long newKRhash;

buffer = malloc(MAXSTRING);

if (buffer == NULL)

{

printf("Bad malloc bye! ");

return 1;

}

while (fgets(buffer, bufferlen, stdin))

{

// printf("data in:%s", buffer);

if (ferror(stdin))

{

printf("Error on stdin ");

break;

}

/*

* Hash 'em up - commences!

*/

newHash = hashDJB2(buffer);

newKRhash = hashKR(buffer);

printf("hash:%016lx:%016lx:%s", newHash, newKRhash, buffer);

}

printf(" Done! ");

return 0;

}