Hash table implementation in C

               A hash table has an array of buckets. It has a key and value. Key is to find the position of the bucket. Value is to be stored on that location. It can be done by two ways as follows.

• ·       Using linked list
• ·       Linear probing

Here, we use linked list to implement the hash table.

Code:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

//The size of the hash table is defined as 4.

#define SIZE 4

//create a node for hash table. it has a key, value and a pointer to point the next node

struct h_Node {

    int h_key;

    int h_value;

    struct h_Node* h_next;

};

// create a hash table

struct h_Node* hashTable[SIZE];

 

// Hash function to find the hash code

int hashCode(int h_key) {

    return h_key % SIZE;

}

// this function adds the key and value to hash table

void insertIt(int h_key, int h_value) {

    int index = hashCode(h_key);

    struct h_Node* newNode = (struct h_Node*)malloc(sizeof(struct h_Node));

    newNode->h_key = h_key;

    newNode->h_value = h_value;

    newNode->h_next = hashTable[index];

    hashTable[index] = newNode;

}

// Display hash table

void displayIt() {

    for (int i = 0; i < SIZE; i++) {

        struct h_Node* temp = hashTable[i];

        printf("Bucket %d: ", i);

        while (temp) {

            printf("(%d, %d) -> ", temp->h_key, temp->h_value);

            temp = temp->h_next;

        }

        printf("NULL\n");

    }

}

int main() {

    insertIt(0,27 );

    insertIt(2, 30);

    insertIt(5, 50);

    insertIt(6, 125);

    insertIt(3, 45);

    displayIt();

    return 0;

}

Output:

Compile and run the program to get the output.

Bucket 0: (0, 27) -> NULL

Bucket 1: (5, 50) -> NULL

Bucket 2: (6, 125) -> (2, 30) -> NULL

Bucket 3: (3, 45) -> NULL

Yes. The code is executed Successfully.

This program creates a hash table with some entries and displayed the data in the buckets. Hope, this code is useful to you. Keep coding!!!