Lab Program 12 Hashing 15CSL38 Data Structures in C Lab

Lab program 12

Given a File of N employee records with a set K of Keys(4-digit) which uniquely determine the records in file F.
Assume that file F is maintained in memory by a Hash Table(HT) of m memory locations with L as the set of memory addresses (2-digit) of locations in HT.
Let the keys in K and addresses in L are integers.
Design and develop a Program in C that uses Hash function H: K -> L as H(K)=K mod m (remainder method), and implement hashing technique to map a given key K to the address space L.
Resolve the collision (if any) using linear probing.

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

int key[20],n,m;
int *ht,index;
int count = 0;

void insert(int key)
{
            index = key % m;
            while(ht[index] != -1)
            {
                         index = (index+1)%m;
            }
            ht[index] = key;
            count++;
 }

void display()
{
           int i;
           if(count == 0)
          {
                         printf("\nHash Table is empty");
                         return;
           }

           printf("\nHash Table contents are:\n ");
           for(i=0; i<m; i++)
                      printf("\n T[%d] --> %d ", i, ht[i]);
}


void main()
{
         int i;
         printf("\nEnter the number of employee  records (N) :   ");
         scanf("%d", &n);

         printf("\nEnter the two digit memory locations (m) for hash table:   ");
         scanf("%d", &m);

         ht = (int *)malloc(m*sizeof(int));
         for(i=0; i<m; i++)
                     ht[i] = -1;

         printf("\nEnter the four digit key values (K) for N Employee Records:\n  ");
         for(i=0; i<n; i++)
                    scanf("%d", &key[i]);

         for(i=0;i<n;i++)
        {
                   if(count == m)
                   {
                        printf("\n~~~Hash table is full. Cannot insert the record %d key~~~",i+1);
                        break;
                   }
                   insert(key[i]);
    }

            //Displaying Keys inserted into hash table
             display();
}

Output:

Enter the number of employee  records (N) :   12

Enter the two digit memory locations (m) for hash table:   15

Enter the four digit key values (K) of 'N' Employee Records:

1234

5678

3456

2345

6799

1235

7890

3214

3456

1235

5679

2346

Hash Table contents are:

 T[0] --> 7890

 T[1] --> -1

 T[2] --> -1

 T[3] --> -1

 T[4] --> 1234

 T[5] --> 2345

 T[6] --> 3456

 T[7] --> 6799

 T[8] --> 5678

 T[9] --> 1235

 T[10] --> 3214

 T[11] --> 3456

 T[12] --> 1235

 T[13] --> 5679

 T[14] --> 2346