Hashing-Chains-Linked-Lists.c

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

struct hash *hashTable = NULL;
int eleCount = 0;

struct node {
int key, age;
char name[100];
struct node *next;
};
struct hash {
struct node *head;
int count;
};
struct node * createNode(int key, char *name, int age) {
struct node *newnode;
newnode = (struct node *) malloc(sizeof(struct node));
newnode->key = key;
newnode->age = age;
strcpy(newnode->name, name);
newnode->next = NULL;
return newnode;
}
void insertToHash(int key, char *name, int age) {
int hashIndex = key % eleCount;
struct node *newnode = createNode(key, name, age);
/* head of list for the bucket with index "hashIndex" */
if (!hashTable[hashIndex].head) {
hashTable[hashIndex].head = newnode;
hashTable[hashIndex].count = 1;
return;
}
/* adding new node to the list */
newnode->next = (hashTable[hashIndex].head);
/*
* update the head of the list and no of
* nodes in the current bucket
*/
hashTable[hashIndex].head = newnode;
hashTable[hashIndex].count++;
return;
}

void deleteFromHash(int key) {
/* find the bucket using hash index */
int hashIndex = key % eleCount, flag = 0;
struct node *temp, *myNode;
/* get the list head from current bucket */
myNode = hashTable[hashIndex].head;
if (!myNode) {
printf("Given data is not present in hash Table!!\n");
return;
}
temp = myNode;
while (myNode != NULL) {
/* delete the node with given key */
if (myNode->key == key) {
flag = 1;
if (myNode == hashTable[hashIndex].head)
hashTable[hashIndex].head = myNode->next;
else
temp->next = myNode->next;

hashTable[hashIndex].count--;
free(myNode);
break;
}
temp = myNode;
myNode = myNode->next;
}
if (flag)
printf("Data deleted successfully from Hash Table\n");
else
	        printf("Given data is not present in hash Table!!!!\n");
	    return;
	}

	void searchInHash(int key) {
	    int hashIndex = key % eleCount, flag = 0;
	    struct node *myNode;	    myNode = hashTable[hashIndex].head;
	    if (!myNode) {
	        printf("Search element unavailable in hash table\n");
	        return;
	    }
	    while (myNode != NULL) {
	        if (myNode->key == key) {
	            printf("VoterID  : %d\n", myNode->key);
	            printf("Name     : %s\n", myNode->name);
	            printf("Age      : %d\n", myNode->age);
	            flag = 1;
	            break;
	        }
        myNode = myNode->next;
	    }
	    if (!flag)
	        printf("Search element unavailable in hash table\n");
	    return;
	}

	void display() {
	    struct node *myNode;
	    int i;
	    for (i = 0; i < eleCount; i++) {
	        if (hashTable[i].count == 0)
	            continue;
	        myNode = hashTable[i].head;
	        if (!myNode)
	            continue;
	        printf("\nData at index %d in Hash Table:\n", i);
	        printf("VoterID     Name          Age   \n");
	        printf("--------------------------------\n");
	        while (myNode != NULL) {
	            printf("%-12d", myNode->key);
	            printf("%-15s", myNode->name);
	            printf("%d\n", myNode->age);
	            myNode = myNode->next;
	        }
	    }
	    return;
	}

	int main() {
	    int n, ch, key, age;
	    char name[100];
	    printf("Enter the number of elements:");
	    scanf("%d", &n);
	    eleCount = n;
	    /* create hash table with "n" no of buckets */
	    hashTable = (struct hash *) calloc(n, sizeof(struct hash));
	    while (1) {
	        printf("\n1. Insertion\t2. Deletion\n");
	        printf("3. Searching\t4. Display\n5. Exit\n");
	        printf("Enter your choice:");
	        scanf("%d", &ch);
	        switch (ch) {
	        case 1:
	            printf("Enter the key value:");
	            scanf("%d", &key);
	            getchar();
	            printf("Name:");
	            fgets(name, 100, stdin);
	            name[strlen(name) - 1] = '\0';
	            printf("Age:");
	            scanf("%d", &age);
	            /*inserting new node to hash table */
	            insertToHash(key, name, age);
	            break;

	        case 2:
	            printf("Enter the key to perform deletion:");
	            scanf("%d", &key);
	            /* delete node with "key" from hash table */
	            deleteFromHash(key);
	            break;

	        case 3:
	            printf("Enter the key to search:");
	            scanf("%d", &key);
	            searchInHash(key);
	            break;
	        case 4:
	            display();
	            break;
	        case 5:
	            exit(0);
	        default:
	            printf("U have entered wrong option!!\n");
	            break;
	        }
	    }
	    return 0;
	}