C Program To Implement Dictionary Using Hashing Algorithms |work|

Dictionaries are fundamental data structures used in compilers, databases, caches, and many system-level applications. While C does not provide a built-in dictionary type, implementing one using hashing is a classic systems programming exercise. The primary challenges are:

Keys are null-terminated strings (char*). Values are integers (int) for demonstration; this can be made generic using void* .

| Method | Pros | Cons | |--------|------|------| | | Simple, handles high load, no clustering | Extra memory for pointers | | Linear Probing | Cache-friendly, no pointers | Primary clustering, deletion complex | | Quadratic Probing | Reduces primary clustering | Secondary clustering | | Double Hashing | Excellent distribution | More computation | c program to implement dictionary using hashing algorithms

// Cleanup destroy_hash_table(dict);

#define TABLE_SIZE 10007 // Prime number for better distribution Values are integers (int) for demonstration; this can

// Key doesn't exist: create new node and insert at head of linked list KeyValuePair *new_pair = create_pair(key, value); if (!new_pair) return;

If we choose m to be roughly proportional to n (i.e., keep α constant, say 0.7–1.0), then α = O(1) , and all operations are (the key length is usually bounded by a constant in practice). If found, we unlink it and free its memory

free_entry(current); printf("Key '%s' deleted.\n", key); return;

return hashCode % HASH_TABLE_SIZE;

Deleting a key involves searching the chain while keeping track of the previous entry. If found, we unlink it and free its memory.