#define HASHSIZE 31

#define HASH_STATUS_EMPTY  0
#define HASH_STATUS_FULL   1
#define HASH_STATUS_USED   2

struct stringval {
   char *str;
   int val;
};

struct hashentry {
   struct stringval sval;
   int status;
};

/* Return a hash table initialized to empty. */
struct hashentry *hashinit();

/* Insert sval into the hashtable htp.
   Return 1 on success and 0 on failure. */
int hashinsert(struct stringval sval, struct hashentry *htp);

/* Remove sval from the hashtable htp.
   Return 1 on success and 0 on failure. */
int hashremove(struct stringval sval, struct hashentry *htp);

/* Return a pointer to the entry for str in the hashtable htp.
   Return NULL if not found. */
struct stringval *hashfind(char *str, struct hashentry *htp);