print-stats.txt

/* -*- mode: c -*- */

/* These functions should be added to your htable.c file */


/**
 * Prints out a table showing what the following attributes were like
 * at regular intervals (as determined by num_stats) while the
 * hashtable was being built.
 *
 * @li Percent At Home - how many keys were placed without a collision
 * occurring.
 * @li Average Collisions - how many collisions have occurred on
 *  average while placing all of the keys so far.
 * @li Maximum Collisions - the most collisions that have occurred
 * while placing a key.
 *
 * @param h the hashtable to print statistics summary from.
 * @param stream the stream to send output to.
 * @param num_stats the maximum number of statistical snapshots to print.
 */
void htable_print_stats(htable h, FILE *stream, int num_stats) {
   int i;

   fprintf(stream, "\n%s\n\n", 
           h->method == LINEAR_P ? "Linear Probing" : "Double Hashing"); 
   fprintf(stream, "Percent   Current    Percent    Average      Maximum\n");
   fprintf(stream, " Full     Entries    At Home   Collisions   Collisions\n");
   fprintf(stream, "------------------------------------------------------\n");
   for (i = 1; i <= num_stats; i++) {
      print_stats_line(h, stream, 100 * i / num_stats);
   }
   fprintf(stream, "------------------------------------------------------\n\n");
}

/**
 * Prints out a line of data from the hash table to reflect the state
 * the table was in when it was a certain percentage full.
 * Note: If the hashtable is less full than percent_full then no data
 * will be printed.
 *
 * @param h - the hash table.
 * @param stream - a stream to print the data to.
 * @param percent_full - the point at which to show the data from.
 */
static void print_stats_line(htable h, FILE *stream, int percent_full) {
   int current_entries = h->capacity * percent_full / 100;
   double average_collisions = 0.0;
   int at_home = 0;
   int max_collisions = 0;
   int i = 0;

   if (current_entries > 0 && current_entries <= h->num_keys) {
      for (i = 0; i < current_entries; i++) {
         if (h->stats[i] == 0) {
            at_home++;
         } 
         if (h->stats[i] > max_collisions) {
            max_collisions = h->stats[i];
         }
         average_collisions += h->stats[i];
      }
    
      fprintf(stream, "%4d %10d %11.1f %10.2f %11d\n", percent_full, 
              current_entries, at_home * 100.0 / current_entries,
              average_collisions / current_entries, max_collisions);
   }
}