Hash Tables in C++

#include<iostream>
using std::cout; using std::endl;
#include <map> 
using std::map;
#include<string>
#include<list>
using std::list;

class Hash
{
  protected:
      int BUCKET;    // No. of buckets
    
      // Pointer to an array containing buckets
      list<int> *table;
  public:
      Hash(int V);  // Constructor
    
      // inserts a key into hash table
      void insertItem(int x);
    
      // deletes a key from hash table
      void deleteItem(int key);
    
      // hash function to map values to key
      int hashFunction(int x) {
          return (x % BUCKET);
      }
    
      void displayHash();
};

  
Hash::Hash(int b)
{
    this->BUCKET = b;
    table = new list<int>[BUCKET];
}
  
void Hash::insertItem(int key)
{
    int index = hashFunction(key);
    table[index].push_back(key); 
}
  
void Hash::deleteItem(int key)
{
  // get the hash index of key
  int index = hashFunction(key);
  
  // find the key in (inex)th list
  list <int> :: iterator i;
  for (i = table[index].begin();
           i != table[index].end(); i++) {
    if (*i == key)
      break;
  }
  
  // if key is found in hash table, remove it
  if (i != table[index].end())
    table[index].erase(i);
}
  
// function to display hash table
void Hash::displayHash() {
  for (int i = 0; i < BUCKET; i++) {
    cout << i;
    for (auto x : table[i])
      cout << " --> " << x;
    cout << endl;
  }
}

#include "hash_table.h"

// Driver program 
int main()
{
  // array that contains keys to be mapped
  int a[] = {15, 11, 27, 8, 12, 69,12,100,90};
  int n = sizeof(a)/sizeof(a[0]);
  
  // insert the keys into the hash table
  Hash h(7);   // 7 is count of buckets in
               // hash table
  for (int i = 0; i < n; i++) 
    h.insertItem(a[i]);  
  
  // delete 12 from hash table
  h.deleteItem(12);
  
  // display the Hash table
  h.displayHash();
 
}

0
1 --> 15 --> 8
2 --> 100
3
4 --> 11
5 --> 12
6 --> 27 --> 69 --> 90