#include <stdio.h>

unsigned long djb2(const char *str) {
    unsigned long h = 5381;
    int c;

    while ((c = *str++)) {
        h = ((h << 5) + h) + c;

        // Essentially equal to:
        // h = h * 33 + c;
    }

    return h;
}

int main(void) {
    char *a = "ABC";
    printf("Hash: %ld\n", djb2(a));

    return 0;
}