C Program To Implement Dictionary Using Hashing Algorithms High Quality Info
// Delete a key-value pair void deleteItem(struct HashTable* ht, int key) int index = hashFunction(key); struct DictionaryItem* current = ht->table[index]; struct DictionaryItem* prev = NULL;
The insert function updates the value if the key already exists. Otherwise, it prepends a new node to the linked list at that hash index.
free(dict->buckets); free(dict);
free(table->buckets); free(table);
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A dictionary (map) stores key–value pairs allowing fast insert, search, and delete. Hashing provides average O(1) operations by computing an index from a key using a hash function and resolving collisions. This article explains design choices, collision resolution strategies, and presents a clear C implementation of a dictionary for string keys and integer values using separate chaining with linked lists.
In computer science, a dictionary (also known as a symbol table, map, or associative array) is an abstract data type that stores key-value pairs, allowing for efficient insertion, deletion, and retrieval of values based on their unique keys. From compilers managing variable names to databases indexing records, dictionaries are fundamental. Among the various ways to implement a dictionary, hashing stands out as one of the most efficient, offering average-case (O(1)) time complexity for core operations. This essay explores the design and implementation of a dictionary in the C programming language using hashing algorithms, delving into hash functions, collision resolution strategies, and practical coding considerations. c program to implement dictionary using hashing algorithms
for (int i = 0; i < old_size; i++) Entry *curr = old_buckets[i]; while (curr) dict_put(dict, curr->key, curr->value); Entry *tmp = curr; curr = curr->next; free(tmp);
free_dict(old_dict); *dict = new_dict;
Below is the full implementation. We'll break it down piece by piece. // Delete a key-value pair void deleteItem(struct HashTable*
return NULL; // Not found
| Operation | Complexity | |-----------|------------| | Insert | O(1 + α) | | Search | O(1 + α) | | Delete | O(1 + α) |
Since the number of possible keys usually exceeds the array size, collisions are inevitable. This implementation uses . Each array index points to a linked list of nodes sharing the same hash index. Architecture and Data Structures Hashing provides average O(1) operations by computing an
: If the bucket is full, you just look at the very next one (Linear Probing) until you find an empty spot. Building the Library in C


