HashTable.cpp

#include <iostream>

#include <list>

using namespace std;

class HashTable

{

  int capacity;

  list<int> *table;

public:

  HashTable(int V);

  void insertItem(int key, int data);

  void deleteItem(int key);

  int checkPrime(int n)

  {

  int i;

  if (n == 1 || n == 0)

  {

    return 0;

  }

  for (i = 2; i < n / 2; i++)

  {

    if (n % i == 0)

    {

    return 0;

    }

  }

  return 1;

  }

  int getPrime(int n)

  {

  if (n % 2 == 0)

  {

    n++;

  }

  while (!checkPrime(n))

  {

    n += 2;

  }

  return n;

  }

  int hashFunction(int key)

  {

  return (key % capacity);

  }

  void displayHash();

};

HashTable::HashTable(int c)

{

  int size = getPrime(c);

  this->capacity = size;

  table = new list<int>[capacity];

}

void HashTable::insertItem(int key, int data)

{

  int index = hashFunction(key);

  table[index].push_back(data);

}

void HashTable::deleteItem(int key)

{

  int index = hashFunction(key);

  list<int>::iterator i;

  for (i = table[index].begin();

   i != table[index].end(); i++)

  {

  if (*i == key)

    break;

  }

  if (i != table[index].end())

  table[index].erase(i);

}

void HashTable::displayHash()

{

  for (int i = 0; i < capacity; i++)

  {

  cout << "table[" << i << "]";

  for (auto x : table[i])

    cout << " --> " << x;

  cout << endl;

  }

}

int main()

{

  int key[] = {231, 321, 212, 321, 433, 262};

  int data[] = {123, 432, 523, 43, 423, 111};

  int size = sizeof(key) / sizeof(key[0]);

  HashTable h(size);

  for (int i = 0; i < size; i++)

  h.insertItem(key[i], data[i]);

  h.deleteItem(12);

  h.displayHash();

}