Question

For this problem, you have to use following hash function: key modulo the number of buckets.

Input format: This program takes a file name as argument from the command line. The file is either blank or contains successive lines of input. Each line contains a character, either ‘i’ or ‘s’, followed by a tab and then an integer, the same format as in the Second Part. For each of the lines that starts with ‘i’, your program should insert that number in the hash table if it is not present. If the line starts with a ‘s’, your program should search the hash table for that value.

Output format: For each line in the input file, your program should print the status/result of that operation. For an insert, the program should print “inserted” if the value is inserted or “duplicate” if the value is already present. For a search, the program should print ”present” or “absent” based on the outcome of the search. Your program should print “error” (and nothing else) if the file does not exist. The program should also print “error” for input lines with improper structure.

Example Execution: Lets assume we have 2 text files with the following contents: "file1.txt" is empty file2.txt: i 10 i 12 s 10 i 10 s 5 The the results will be: third file1.txt third file2.txt inserted inserted present error duplicate absent /third file3 .txt error

In C, please. Thanks.

Answer 1

C Program:

/* C Program that implements Hash table */

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

//Function prototypes
void insertOperation(int[], int, int);
void searchOperation(int[], int, int);

//Main function
int main(int argc, char *argv[])
{
   //Hash table
   int hashTable[10];
   int key, i;
   char operation;

   FILE *fp;
  
   //Opening file in read mode
   fp = fopen(argv[1], "r");

   //If file doesn't exist
   if(!fp)
   {
       printf("\n Error \n");
       return 0;
   }
  
   //Initializing hash table with -1
   for(i=0; i<10; i++)
       hashTable[i] = -1;

   //Reading data from file
   while(fscanf(fp, " %c %d ", &operation, &key) == 2)
   {
       //Calling appropriate function based on type of operation
       switch(operation)
       {
           //Insert operation
           case 'i':
                   insertOperation(hashTable, 10, key);
                   break;
          
           //Search Operation
           case 's':  
                   searchOperation(hashTable, 10, key);
                   break;

           default:  
                   printf("\n Error \n");
                   break;
       }
   }

   //Closing file
   fclose(fp);
}

//Function that inserts a value in to hash table
void insertOperation(int hashTable[], int size, int key)
{
   int hashValue;

   //Calculating hash value
   hashValue = key % size;

   //If there is a vacant space insert the element
   if(hashTable[hashValue] == -1)
   {
       hashTable[hashValue] = key;
       printf("\n Inserted \n");      
   }
   else
   {
       //Bucket is not empty  
       printf("\n Duplicate \n");      
   }          
}

//Function that searches for a value in hash table
void searchOperation(int hashTable[], int size, int key)
{
   int hashValue;
  
   //Calculating hash value
   hashValue = key % size;
  
   //Searching in hash table
   if(hashTable[hashValue] == key)
   {
       printf("\n Present \n");      
   }
   else
   {
       printf("\n Absent \n");      
   }          
}

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anil@ubuntu: anil@ubuntu: $ gcc hashing.c anil@ubuntu:- a.out file2.txt Inserted Inserted Present Error Duplicate Absent anil@ubuntu: $