Question

The working code:

//import java.util.Hashtable;

public class HashingExample1 {
   private int[] hashTable = new int[10];
  
   public int hash(int ele){
       return ele % this.hashTable.length;
   }
   public boolean insert(int ele){
       int pos = hash(ele);
       System.out.println("Hashing key " + pos);
       if(this.hashTable[pos] == 0)
           this.hashTable[pos] = ele;
       else{
           for(int i = pos + 1; i < this.hashTable.length; i++){
               if(this.hashTable[i] == 0){
                   this.hashTable[i] = ele;
                   return true;
               }  
           }
       }
       return true;
   }
   public int search(int ele){
       int loc = -1;
       int pos = hash(ele);
       if(hashTable[pos] == ele)
           loc = pos;
       else{
           for(int i = pos + 1; i < this.hashTable.length; i++){
               if(this.hashTable[i] == ele)
                   loc = i;
           }
       }
       return loc;
   }
   public static void main(String[] args) {
       HashingExample1 he = new HashingExample1();
       System.out.println(he.insert(245));
       System.out.println(he.insert(342));
       System.out.println(he.insert(156));
       System.out.println(he.insert(345));
       System.out.println(he.insert(999));
       System.out.println(he.insert(109));
       System.out.println("Element in hash table");
       for(int i = 0; i < he.hashTable.length; i++)
           System.out.printf("Hashtable[%d] ---> %d\n", i, he.hashTable[i]);
       int loc = he.search(342);
       if(loc == -1)
           System.out.println("Element 342 is not found");
       else
           System.out.println("Element 342 is found at index position " + loc);
       loc = he.search(345);
       if(loc == -1)
           System.out.println("Element 345 is not found");
       else
           System.out.println("Element 345 is found at index position " + loc);
      
       String str = "ABCDEF";
       System.out.println(str.hashCode());

   }

}

The Questions :

• Ask user to insert 5 different values in a hash table.
• Ask user to enter key value and search about and display the result.
• Allow user to delete key send to delete method and display the result.

(DATA STRUCTURE BY JAVA)

Answer 1

If you have any problem with the code feel free to comment.

Program

import java.util.Scanner;

class HashingExample1 {
   private int[] hashTable = new int[10];

   public int hash(int ele) {
       return ele % this.hashTable.length;
   }

   public boolean insert(int ele) {
       int pos = hash(ele);
       System.out.println("Hashing key " + pos);
       if (this.hashTable[pos] == 0)
           this.hashTable[pos] = ele;
       else {
           for (int i = pos + 1; i < this.hashTable.length; i++) {
               if (this.hashTable[i] == 0) {
                   this.hashTable[i] = ele;
                   return true;
               }
           }
       }
       return true;
   }

   public int search(int ele) {
       int loc = -1;
       int pos = hash(ele);
       if (hashTable[pos] == ele)
           loc = pos;
       else {
           for (int i = pos + 1; i < this.hashTable.length; i++) {
               if (this.hashTable[i] == ele)
                   loc = i;
           }
       }
       return loc;
   }

   //for deleting values
   public void delete(int ele) {
       int index = search(ele);
       if (index == -1) {
           System.out.println("The " + ele + " is not present in the Hash Table");
           return;
       }
       if (hashTable[index] == 0)
           System.out.println("There is no element to delete");
       else {
           System.out.println("The " + ele + " is deleted");
           hashTable[index] = 0;
       }
   }

   //for displaying hash table
   public void displayHashTable() {
       System.out.println("Element in hash table");
       for (int i = 0; i < hashTable.length; i++)
           System.out.printf("Hashtable[%d] ---> %d\n", i, hashTable[i]);
   }
}

public class Test{
   public static void main(String[] args) {
       Scanner sc = new Scanner (System.in);
       HashingExample1 he = new HashingExample1();
      
       //asking 5 values
       System.out.println("Enter Five values: ");
       for(int i=1; i<=5; i++) {
           System.out.print("Value "+i+": ");
           he.insert(sc.nextInt());
       }
      
       System.out.println();
       he.displayHashTable();
      
      
       //asking values to be searched
       System.out.println();
       System.out.print("Enter a value to be serached: ");
       int search = sc.nextInt();
       System.out.println("Value is at index: "+he.search(search));
       he.displayHashTable();
      
       //asking value to be deleted
       System.out.println();
       System.out.print("Enter a value to be deleted: ");
       int delete = sc.nextInt();
       he.delete(delete);
       he.displayHashTable();
      
       sc.close();
   }
}

Outputs