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Hash Table Implementation in C with Open Addressing

This C code exemplifies a hash table employing open addressing to manage collisions. The program reads a file, sanitizes and inserts unique words into the hash table, and calculates statistics such as total and unique words, hash size, and row-wise information. The implementation includes structures for words and the hash table, functions for hashing, word sanitization, membership check, insertion, and memory deallocation. The main function orchestrates user input, file reading, and output generation. This program showcases a robust approach to handling collisions and provides a foundation for understanding basic hash table principles in the C programming language.

Exploring Hash Table Implementation in C

This C code offers a comprehensive illustration of a hash table utilizing open addressing, providing a practical example of collision resolution strategies. Designed to handle unique words from a file, it calculates and prints diverse statistics about the data, demonstrating key principles of hash table implementation in C. The structured program comprises essential functionalities such as hashing, word sanitization, membership checks, insertion, and memory management. With its user-friendly entry point, the code serves as a valuable educational resource for understanding hash tables in C. Whether you're learning about hash tables or need help with your C assignment, this code offers insight into practical implementation and fundamental concepts in data structures and algorithms.

Block 1: Header Files

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


  • The code includes standard C libraries for input/output operations, dynamic memory allocation, string manipulation, and boolean values.

Block 2: Word Structure

typedef struct _Word { char* value; struct _Word* next; } Word;


  • Defines a structure named Word that represents a node in the linked list. Each node contains a string value (value) and a pointer to the next node (next).

Block 3: OpenHash Structure

typedef struct _OpenHash { Word** words; int size; } OpenHash;


  • Defines a structure named OpenHash representing the hash table. It contains an array of pointers to words (words) and the size of the table (size).

Block 4: newOpenHash Function

OpenHash* newOpenHash(int size) { // Function implementation }


  • Allocates memory for a new hash table and initializes its properties.
  • Returns a pointer to the newly created hash table.

Block 5: hash Function

int hash(char* word, int n) { // Function implementation }


  • Implements a simple hash function for strings.
  • Returns the hashed index for the given string based on its characters and the size of the array.

Block 6: sanitizeWord Function

char* sanitizeWord(char* word) { // Function implementation }


  • Creates a new string by removing non-alphabetic characters from the input string and converting it to lowercase.
  • Returns a pointer to the newly created string.

Block 7: member Function

bool member(char* word, OpenHash* table) { // Function implementation }


  • Checks if a given word is present in the hash table.
  • Uses the hash function to find the index, then searches the linked list at that index for the word.
  • Returns true if the word is found, false otherwise.

Block 8: insert Function

void insert(char* value, OpenHash* table) { // Function implementation }


  • Inserts a new word into the hash table.
  • Uses the hash function to find the index and then adds the word to the linked list at that index, avoiding duplicates.

Block 9: listLength Function

int listLength(Word* list) { // Function implementation }


  • Counts the number of elements in a linked list.
  • Returns the length of the linked list.

Block 10: tableLength Function

int tableLength(OpenHash* table) { // Function implementation }


  • Counts the total number of elements in the entire hash table by summing up the lengths of all linked lists.

Block 11: printTableRowStats Function

void printTableRowStats(OpenHash* table) { // Function implementation }


  • Prints statistics about each row in the hash table, specifically the number of values in each row.

Block 12: freeList Function

void freeList(Word* list) { // Function implementation }


  • Deallocates memory used by the linked list.

Block 13: freeTable Function

void freeTable(OpenHash* table) { // Function implementation }


  • Deallocates memory used by the entire hash table, including all linked lists.

Block 14: main Function

int main() { // Function implementation }


  • Entry point of the program.
  • Initializes a hash table, reads words from a file, inserts unique words into the hash table, and prints various statistics about the table.
  • Deallocates memory before exiting.


In conclusion, this C program embodies a fundamental implementation of a hash table, showcasing the principles of open addressing for collision resolution. With structures defining words and the hash table itself, the code incorporates functions for table manipulation, string sanitization, and statistical analysis. Notably, the program emphasizes data integrity, preventing duplicate entries through careful insertion procedures. The main function orchestrates these components, efficiently reading from a file, constructing the hash table, and offering insightful statistics on word distribution. In its entirety, this code not only serves as a practical example of a hash table but also underscores the importance of proper memory management and algorithmic considerations in handling real-world data structures.