source code in c hash bucket

1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4 
5#define CAPACITY 50000 // Size of the Hash Table
6 
7unsigned long hash_function(char* str) {
8    unsigned long i = 0;
9    for (int j=0; str[j]; j++)
10        i += str[j];
11    return i % CAPACITY;
12}
13 
14typedef struct Ht_item Ht_item;
15 
16// Define the Hash Table Item here
17struct Ht_item {
18    char* key;
19    char* value;
20};
21 
22typedef struct HashTable HashTable;
23 
24// Define the Hash Table here
25struct HashTable {
26    // Contains an array of pointers
27    // to items
28    Ht_item** items;
29    int size;
30    int count;
31};
32 
33Ht_item* create_item(char* key, char* value) {
34    // Creates a pointer to a new hash table item
35    Ht_item* item = (Ht_item*) malloc (sizeof(Ht_item));
36    item->key = (char*) malloc (strlen(key) + 1);
37    item->value = (char*) malloc (strlen(value) + 1);
38     
39    strcpy(item->key, key);
40    strcpy(item->value, value);
41 
42    return item;
43}
44 
45HashTable* create_table(int size) {
46    // Creates a new HashTable
47    HashTable* table = (HashTable*) malloc (sizeof(HashTable));
48    table->size = size;
49    table->count = 0;
50    table->items = (Ht_item**) calloc (table->size, sizeof(Ht_item*));
51    for (int i=0; i<table->size; i++)
52        table->items[i] = NULL;
53 
54    return table;
55}
56 
57void free_item(Ht_item* item) {
58    // Frees an item
59    free(item->key);
60    free(item->value);
61    free(item);
62}
63 
64void free_table(HashTable* table) {
65    // Frees the table
66    for (int i=0; i<table->size; i++) {
67        Ht_item* item = table->items[i];
68        if (item != NULL)
69            free_item(item);
70    }
71 
72    free(table->items);
73    free(table);
74}
75 
76void handle_collision(HashTable* table, unsigned long index, Ht_item* item) {
77}
78 
79void ht_insert(HashTable* table, char* key, char* value) {
80    // Create the item
81    Ht_item* item = create_item(key, value);
82 
83    // Compute the index
84    unsigned long index = hash_function(key);
85 
86    Ht_item* current_item = table->items[index];
87     
88    if (current_item == NULL) {
89        // Key does not exist.
90        if (table->count == table->size) {
91            // Hash Table Full
92            printf("Insert Error: Hash Table is full\n");
93            // Remove the create item
94            free_item(item);
95            return;
96        }
97         
98        // Insert directly
99        table->items[index] = item; 
100        table->count++;
101    }
102 
103    else {
104            // Scenario 1: We only need to update value
105            if (strcmp(current_item->key, key) == 0) {
106                strcpy(table->items[index]->value, value);
107                return;
108            }
109     
110        else {
111            // Scenario 2: Collision
112            // We will handle case this a bit later
113            handle_collision(table, index, item);
114            return;
115        }
116    }
117}
118 
119char* ht_search(HashTable* table, char* key) {
120    // Searches the key in the hashtable
121    // and returns NULL if it doesn't exist
122    int index = hash_function(key);
123    Ht_item* item = table->items[index];
124 
125    // Ensure that we move to a non NULL item
126    if (item != NULL) {
127        if (strcmp(item->key, key) == 0)
128            return item->value;
129    }
130    return NULL;
131}
132 
133void print_search(HashTable* table, char* key) {
134    char* val;
135    if ((val = ht_search(table, key)) == NULL) {
136        printf("Key:%s does not exist\n", key);
137        return;
138    }
139    else {
140        printf("Key:%s, Value:%s\n", key, val);
141    }
142}
143 
144void print_table(HashTable* table) {
145    printf("\nHash Table\n-------------------\n");
146    for (int i=0; i<table->size; i++) {
147        if (table->items[i]) {
148            printf("Index:%d, Key:%s, Value:%s\n", i, table->items[i]->key, table->items[i]->value);
149        }
150    }
151    printf("-------------------\n\n");
152}
153 
154int main() {
155    HashTable* ht = create_table(CAPACITY);
156    ht_insert(ht, "1", "First address");
157    ht_insert(ht, "2", "Second address");
158    print_search(ht, "1");
159    print_search(ht, "2");
160    print_search(ht, "3");
161    print_table(ht);
162    free_table(ht);
163    return 0;
164}
165