C Program To Implement Dictionary Using Hashing Algorithms Jun 2026

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

The same key must always produce the same hash index.

static Node *create_node(const char *key, int value) Node *n = malloc(sizeof(Node)); if (!n) return NULL; n->key = strdup(key); if (!n->key) free(n); return NULL; n->value = value; n->next = NULL; return n;

int main() Dictionary* dict = createDictionary(10); c program to implement dictionary using hashing algorithms

delete(dict, "banana");

#include #include #include #define TABLE_SIZE 101 // Structure for a single dictionary entry typedef struct Entry char *key; char *value; struct Entry *next; // Pointer to next entry in case of collision Entry; // The Hash Table (Dictionary) Entry *dictionary[TABLE_SIZE]; Use code with caution. Copied to clipboard 2. Implement the Hashing Algorithm

*found = 0; return 0; // Return value ignored when found == 0 #include <stdio

free(curr->key); free(curr); dict->count--; return 1; // success

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

#include <pthread.h>

This function adds a new key-value pair or updates the value if the key already exists.

To handle this, we use collision resolution techniques. The two most common are:

), rehash every existing item into the new array, and free the old memory. Feature Summary Table Recommendation Hash Function FNV-1a or djb2 Fast with excellent distribution for string keys. Collision Handling Separate Chaining Easier to manage deletions and avoids clustering. Resizing Rule Load Factor > 0.75 Balances memory usage with average time complexity. Growth Strategy Double Table Size Amortizes the cost of rehashing. For a complete reference, you can look at the K & R C implementation which uses a fixed-size table with chaining for simplicity. Stack Overflow code example combining these features into a single C file? How to implement a hash table (in C) - Ben Hoyt Implement the Hashing Algorithm *found = 0; return

A collision occurs when two different keys generate the exact same array index. Because hash tables have a fixed size, you must handle these duplicates. This implementation uses . Each slot in the hash table points to a linked list of nodes. Multiple keys mapping to the same index are simply appended to that slot's list. Technical Overview of the Implementation

return index; // Empty slot or tombstone