dictionary.c

/**
 * dictionary.c
 *
 * Computer Science 50
 * Problem Set 5
 *
 * Implements a dictionary's functionality.
 */

#include <stdbool.h>
#include <string.h>
#include <stdlib.h>

#include "dictionary.h"

/**
 * Returns true if word is in dictionary else false.
 */
bool check(const char* word)
{
    int word_hash_value = hash_it(word);
    
    node* cursor = hashtable[word_hash_value];
    
    while (cursor != NULL)
    {
        if (strcmp(cursor->word, word) == 0) return true;
        else cursor = cursor->next;
    }
    
    return false;
}

/**
 * Loads dictionary into memory.  Returns true if successful else false.
 */
bool load(const char* dictionary)
{
    // open dictionary
    FILE* dic = fopen(dictionary, "r");
    if (dic == NULL)
    {
        printf("Could not open dictionary.");
        return 1;
    }
    
    // create nodes and put them into the hash table
    while (1)
    {
        // create a new node
        node* new_node = malloc(sizeof(node));
        // put a word into the node
        if (fscanf(dic, "%s", new_node->word) == EOF) return true;
        
        // get hash value
        int hash_val = hash_it(new_node->word);
        
        // put the node into the hash table
        if (hashtable[hash_val] == NULL)
        {
            hashtable[hash_value] = new_node;
        }
        else
        {
            new_node->next = hashtable[hash_value];
            hashtable[hash_value] = new_node;
        }
        
        // count the number of words in dictionary
        count++
        
    }
    return false;
}

/**
 * Returns number of words in dictionary if loaded else 0 if not yet loaded.
 */
unsigned int size(void)
{
    if (count != 0) return count;
    else return 0;
}

/**
 * Unloads dictionary from memory.  Returns true if successful else false.
 */
bool unload(void)
{
    for (int i = 0; i < 65536; i++)
    {
        node* cursor = hashtable[i];
        
        while (cursor != NULL)
        {
            node* temp = cursor;
            cursor = cursor->next;
            free(temp);
        }
    }
    
    return false;
}