c++ code The pseudo code of the hash function is given as follows. int hash(cons

Question

c++ code The pseudo code of the hash function is given as follows. int hash(const string &key) { int value = 1; for (int position = 0; position < max_key_length; position++) value *= key[position]; value %= hash_size; if (value < 0) value += hash_size; return value; } a. the hash function b. A constructor that takes an integer parameter specifying the hash table size (hash_size). c. The retrieve() method that takes a string key as the input and returns the location (index) of the key in the hash table. If the hash table does not have the key, retrieve() returns -1. d. The insert() method that takes a string key as the input and inserts it into the hash table. If the key already exists in the table or if the table is full, the insertion will not be completed and -1 is returned. If the key is inserted, the location (index) of the key in the hash table is returned. e. Class Hash_table1 uses "quadratic probing" for collision resolution. max width of the key is 6

Explanation / Answer

Hi ,

c++ code for the hash function

/*
* C++ Program to Implement Hash function
*/
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
const int TABLE_SIZE = 5;

/*
* HashNode Class Declaration
*/
class HashNode
{
public:
int key;
int value;
HashNode(int key, int value)
{
this->key = key;
this->value = value;
}
};

/*
* DeletedNode Class Declaration
*/
class DeletedNode:public HashNode
{
private:
static DeletedNode *entryvalues;
DeletedNode():HashNode(-1, -1)
{}
public:
static DeletedNode *getNode()
{
if (entryvalues == NULL)
entryvalues = new DeletedNode();
return entryvalues;
}
};
DeletedNode *DeletedNode::entryvalues = NULL;
/*
* HashMap Class Declaration
*/
class HashMap
{
private:
HashNode **htable;
public:
HashMap()
{
htable = new HashNode* [TABLE_SIZE];
for (int i = 0; i < TABLE_SIZE; i++)
{
htable[i] = NULL;
}
}

~HashMap()
{
for (int i = 0; i < TABLE_SIZE; i++)
{
if (htable[i] != NULL && htable[i] != DeletedNode::getNode())
delete htable[i];
}
delete[] htable;
}
/*
* Hash Function
*/
int HashFunc(int key)
{
return key % TABLE_SIZE;
}
/*
* Insert Element at a key
*/
void Insert(int key, int value)
{
int hash_val = HashFunc(key);
int init = -1;
int deletedindex = -1;
while (hash_val != init && (htable[hash_val]
== DeletedNode::getNode() || htable[hash_val]
!= NULL && htable[hash_val]->key != key))
{
if (init == -1)
init = hash_val;
if (htable[hash_val] == DeletedNode::getNode())
deletedindex = hash_val;
hash_val = HashFunc(hash_val + 1);
}
if (htable[hash_val] == NULL || hash_val == init)
{
if(deletedindex != -1)
htable[deletedindex] = new HashNode(key, value);
else
htable[hash_val] = new HashNode(key, value);
}
if(init != hash_val)
{
if (htable[hash_val] != DeletedNode::getNode())
{
if (htable[hash_val] != NULL)
{
if (htable[hash_val]->key == key)
htable[hash_val]->value = value;
}
}
else
htable[hash_val] = new HashNode(key, value);
}
}
/*
* Search Element at a key
*/
int Search(int key)
{
int hash_val = HashFunc(key);
int init = -1;
while (hash_val != init && (htable[hash_val]
== DeletedNode::getNode() || htable[hash_val]
!= NULL && htable[hash_val]->key != key))
{
if (init == -1)
init = hash_val;
hash_val = HashFunc(hash_val + 1);
}
if (htable[hash_val] == NULL || hash_val == init)
return -1;
else
return htable[hash_val]->value;
}
/*
* Remove Element at a key
*/
void Remove(int key)
{
int hash_val = HashFunc(key);
int init = -1;
while (hash_val != init && (htable[hash_val]
== DeletedNode::getNode() || htable[hash_val]
!= NULL && htable[hash_val]->key != key))
{
if (init == -1)
init = hash_val;
hash_val = HashFunc(hash_val + 1);
}
if (hash_val != init && htable[hash_val] != NULL)
{
delete htable[hash_val];
htable[hash_val] = DeletedNode::getNode();
}
}
};

/*
* Main Contains Menu
*/
int main()
{
HashMap hash;
int key, value;
int choice;
while(1)
{
cout<<" ----------------------"<<endl;
cout<<"Operations on Hash Table"<<endl;
cout<<" ----------------------"<<endl;
cout<<"1.Insert element into the table"<<endl;
cout<<"2.Search element from the key"<<endl;
cout<<"3.Delete element at a key"<<endl;
cout<<"4.Exit"<<endl;
cout<<"Enter your choice: ";
cin>>choice;
switch(choice)
{
case 1:
cout<<"Enter element to be inserted: ";
cin>>value;
cout<<"Enter key at which element to be inserted: ";
cin>>key;
hash.Insert(key, value);
break;
case 2:
cout<<"Enter key of the element to be searched: ";
cin>>key;
if(hash.Search(key) == -1)
{
cout<<"No element found at key "<<key<<endl;
continue;
}
else
{
cout<<"Element at key "<<key<<" : ";
cout<<hash.Search(key)<<endl;
}
break;
case 3:
cout<<"Enter key of the element to be deleted: ";
cin>>key;
hash.Remove(key);
break;
case 4:
exit(1);
default:
cout<<" Enter correct option ";
}
}
return 0;
}

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