PRN37yVa

1// Implements a dictionary's functionality
2
3#include <ctype.h>
4#include <stdio.h>
5#include <stdbool.h>
6#include <stdlib.h>
7#include <string.h>
8#include <strings.h>
9
10#include "dictionary.h"
11
12// definition to avoid magic numbers in hash function/table
13#define ALPHABET 26
14
15// node data structure
16typedef struct nodedef
17{
18    char word[LENGTH + 1];
19    struct nodedef *next;
20}
21node;
22
23// hash function prototype
24unsigned int myHash(char *word);
25
26// global variables
27int indexHash = 0;
28int sizeDict = 0;
29
30// array for hash table
31node *hashtable[ALPHABET] = {NULL};
32
33
34
35
36
37// Returns true if word is in dictionary else false
38bool check(const char *word)
39{
40    char tmp[LENGTH + 1];
41    int len = strlen(word);
42
43    for (int i = 0; i < len; i++)
44    {
45        tmp[i] = tolower(word[i]);
46    }
47
48    tmp[len] = '\0';
49
50    // hash word to find index
51    indexHash = myHash(tmp);
52
53    // head pointer node
54    node *head = hashtable[indexHash];
55
56    // cursor pointer points to same memory location as head pointer at index
57    node *cursor = head;
58
59    // traverse linked list
60    while (cursor != NULL)
61    {
62        if (strcasecmp(cursor->word, tmp) != 0)
63            cursor = cursor->next;
64        else
65            return true;
66    }
67
68    return false;
69}
70
71
72
73// Loads dictionary into memory, returning true if successful else false
74bool load(const char *dictionary)
75{
76    // open dictionary file
77    FILE *dict = fopen(dictionary, "r");
78
79    // check if dictionary file exists and can be opened
80    if (!dict)
81    {
82        fprintf(stderr, "Could not open dictionary file.\n");
83        return false;
84    }
85
86    char word[LENGTH + 1];
87
88    // scan dictionary file word by word
89    while (fscanf(dict, "%s", word) != EOF)
90    {
91        // obtain index through hashing the word
92        indexHash = myHash(word);
93
94        //TODO move all of the lines for adding words to a separate addWord() function
95
96        // create new node pointer for new word
97        node *newNode = malloc(sizeof(node));
98
99        // in case there's no memory for new node
100        if (newNode == NULL)
101        {
102            unload();
103            return false;
104        }
105
106        // add word to node
107        strcpy(newNode->word, word);
108
109        // head pointer node
110        node *head = hashtable[indexHash];
111
112        // in case hashtable array at indexHash is empty
113        if (hashtable[indexHash] == NULL)
114        {
115            head = newNode;
116            newNode->next = NULL;
117        }
118        // in case hashtable array at indexHash is not empty
119        else
120        {
121            newNode->next = head;
122            head = newNode;
123        }
124
125        // TODO move all of the above to addWord() function
126
127        // increase dictionary word count
128        sizeDict++;
129
130        free(newNode);
131
132    }
133
134    // close dictionary
135    fclose(dict);
136    return true;
137}
138
139
140
141// Returns number of words in dictionary if loaded else 0 if not yet loaded
142unsigned int size(void)
143{
144    return sizeDict;
145}
146
147
148
149// Unloads dictionary from memory, returning true if successful else false
150bool unload(void)
151{
152
153        // head pointer node
154        node *head = hashtable[indexHash];
155
156    node *cursor = head;
157    while(cursor != NULL)
158    {
159        node *temp = cursor;
160        cursor = cursor->next;
161        free(temp);
162    }
163
164    return false;
165}
166
167
168
169//uber simple temporary hash function to begin solving speller
170unsigned int myHash(char *word)
171{
172    int sum = 0;
173
174    for (int i = 0, j = strlen(word); i < j; i++)
175    {
176        sum += word[i];
177    }
178
179    return sum % ALPHABET;
180}